GB2080687A

GB2080687A - Controlled release of active compounds from a polymer-based dispenser

Info

Publication number: GB2080687A
Application number: GB8122447A
Authority: GB
Original assignee: Environmental Chemicals Inc
Current assignee: Environmental Chemicals Inc
Priority date: 1980-07-24
Filing date: 1981-07-21
Publication date: 1982-02-10
Also published as: PH21778A; GB2080687B; PH20474A; AU554834B2; AU7346181A; NZ197693A

Abstract

A composition and method for the controlled release of compounds eg larvicides, molluscicides, nematicides, trace nutrients or plant regulants or herbicides from a plastic dispenser, generally in association with a porosigen in contact with water, for example, an aquatic environment or soil moisture. The porosigen, depending upon the desired end use and release rate of a compound, can have a solubility of less than 0.001 grams per 100 grams of water, up to 100 grams per 100 grams of water. The combination of the plastic dispenser containing the porosigen and compound results in a slow release which can last for days, months, and even years, through dissolution of the porosigen and the formation of a porous network permitting water to contact the dispersed compound located in the interior portions of the dispenser.

Description

SPECIFICATION Controlled release of active compounds from a polymer-based dispenser The present invention relates to the controlled release of compounds utilizing a plastic dispenser with a porosigen contained therein.

More specifically, the invention relates to the controlled release of organotins and other compounds utilized as a molluscicide, the controlled release of larvicides, as well as the controlled release of trace nutrients, nematicides, soil insecticides, herbicides etc., from a plastic dispenser.

It is well known that biocidal materials can be incorporated into an elastomer matrix and caused to release at a rate efficacious with pest destruction.

U.S. Patent No.3,417,181 teaches that organotin toxicants can be dissolved in an elastomer-type matrix and caused to release through a diffusiondissolution mechanism when exposed to water. The crux of this seminal invention was keyed to the necessity of the agent being soluble in the polymer.

Similarly, U.S. Patents 3,590,119; 3,426,473; 3,851,053; and 3,639,583 extend the scope of the art to embrace new formulations encompassing different elastomers, specific release regulants that affect the diffusion path length, and the like, but again the key concept is the necessity of agent solubility in the elastomer. Agents incorporated are organic pesticides, and the generic matrix type is elastomers such as natural rubber, styrene - buta - styrene rubber, and the like. In contrast U.S. Patent No.4,012,221 teaches that inorganic copper salts capable of being released into water are incorporated in a moderately crosslinked elastomer in which the copper salts are insoluble.

It is well known to the compounding art that agents not soluble within a polymeric matrix will not move at an efficacious rate through said matrix to said matrix surface and thus enterthe ambient environment Almost all organic pesticidal agents lack solubility in plastic matrices such as thermoplastic orthermoset. Similarly, inorganic pesticidal agents are likewise insoluble in known thermoplastic or thermosetting polymers. Similarly, inorganic chemicals utilized as trace nutrients in agriculture are insoluble in plastic materials.

One method of causing an insoluble organic agent to emit from a plastic dispensing unit is to use a third phase material that is (1) soluble in some extent in said plastic, and (2) will carry said organic agent in solution or serve as a migratory pathway for said agent to reach the surface of said dispenser. It is, of course, recognized that the incorporated agent must reach the plasticlexternal environment interface to have any effect on organisms inhibiting the external environment. U.S. Patents 2,956,073 and 3,116,201 describe the use of plasticizers as carrier elements.

In an improvement on such patents, U.S. Patents 3,705,938 and 3,864,468 teach that surface loss from a plasticized matrix is subject to control through the use of a regulating membrane at said surface.

The controlled-release art has been generally confined to the incorporation and release of insecticides, bactericides, molluscicides and other toxic materials of an organic nature from an elastomer, wherein solubility is essential, or plasticized plastics, wherein an additive carrier material is critical. Microencapsulation processes, wherein an inner core of the toxic agent is surrounded by a polymeric matrix, is well known to the pest control art. In general, release is effected by the rupture of the enveloping membrane.

Little work has been hitherto performed in the development of efficacious long lasting fertilizing systems. U.S. Patent 3,748,115 teaches that plant nutrients can be bound in a matrix of synthetic rubber, waxes, asphalt, and the like. In this work, four critical elements of the invention are set forth. The fertilizer, emphasizing bulk materials and not trace nutrients, must be uniformly dispersed in a hydrophobic binding element. The dispensing unit must be cylindrical in shape. Said cylinder must be partially coated with a water-insoluble, water-permeable exterior membrane. A portion of the cylinder must be non-coated with said membrane. U.S. Patent 3,520,651 extends this art to teach that more than one nutrient can be incorporated in similar dispensing commodities.

Of course, fertilizing materials have long been compounded with varous binders to facilitate dispersal and, in some cases to prolong availability by water. U.S. Patent 3,336,129 teaches that the use of small amounts of water insoluble copolymers and terpolymers of ethers, substituted ethers, ethylene oxide, and the like, will serve as carriers for fertilizing materials, said copolymers and terpolymers must be crosslinked. Materials are comprised of polymer + fertilizer + water + soil components and the plant is grown within this medium.

Also, fertilizers such as urea can be coated in a granular form as taught in U.S. Patent 3,336,155, thus retarding solution in ground waters. U.S. Patent 3,276,857 teaches that a fertilizer can be encapsulated with asphalt or various waxes and thus, emission into the environment is slowed.

Other encapsulated patents include Japanese Patent 4,428,457 wherein a granulated fertilizer leaches through a thin film; U.S. Patent No.

3,059,379 wherein a fertilizer is encapsulated with the encapsulating film having holes or apertures therein; and U.S. Patent No. 4,019,890 wherein granular fertilizers are coated with a water-resisting layer and forming a jelly-like gel coating thereon.

U.S. Patent No.2,891,355 relates to coating shredded styrofoam with a solution of fertilizers and nut rients, adding water, and potting a plant therein. Brit ish Patent No. 68,127 relates to utilizing very small amounts of a thermoplastic material as a binder to prevent bulk fertilizers such as urea, and other deli quescent nitrogen compounds from sticking together. Other patents in the area which do not relate to the present invention are Japanese Patent 4,943,776 and U.S. Patent Nos. 3,794,478; 2,791,496; 2,797,985; 3,372,019; and 4,111,684.

Turning to the area of larvicides, Boike et al has shown in examining 23 different organotin formulations and solute elastomer formulations that they were not effective under practical use conditions due to the presence of natural or organic substances common to water courses. Said organic materials rapidly absorb organotin molecules, essentially removing them from mosquito larva contact. In a text by Ca rdarelli, 1976, it was taught that pesticides in an elastomer matrix can cause a slow-long duration release of the pesticide.

U.S. Patent No. 4,012,347 relates to a rosin composition containing a film forming polymer, a solvent, and a pigment in which the rosin slowly flakes off, thereby exposing an organotin compound. U.S.

Patent No. 3,234,032 also relates to anti-fouling marine coating compositions wherein various organotin compounds are contained in waxes, oils, or paints. U.S. Patent No.3,236,739 relates to a bis(tributyltin) - adipate and anti-fouling composition wherein the tin compound is dispersed in substantially water-insoluble film forming vehicles such as spar varnish, vinyl acetate-vinyl chloride copolymer paints, and the like.

In an article appearing in CHEMICAL ABSTRACTS, 75:97577c (t971), various non-organotin liquid pesticides are dispersed in various film-forming polymers, however, the system does not contain a porosigen or a water release system.

U.S. Patent No.4,010,141 relates to an organotin compound having a normal-dodecyl side chain such that the tin compound is soluble in and has bleedability from a thermoplastic. However, this patent fails to teach the use of a porosigen and actually teaches away from applicant's invention.

Accordingly, it is an object of the present invention to provide for the slow release of compounds from a plastic dispenser.

It is yet another object of the present invention to provide for the slow and/or controlled release of a compound from a dispenser, as above, containing a thermoplastic matrix or a thermoset plastic matrix.

It is yet another object of the present invention to provide a dispenser, as above, containing a nonsoluble thermoplastic or a thermoset plastic matrix.

It is yet another object of the present invention to provideforthe slow release of compounds from a thermoplastic dispenser, as above, wherein said thermoplastic includes polyethylene, low density polyethylene and high density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, polyvinyl acetate, polyamide, polyester, polyurethane, and combinations thereof.

It is another object of the present invention to provide for the slow release of compounds from a thermoset dispenser, as above, containing a thermoset such as phenolic, epoxy, amino resins, unsaturated polyesters, urethane foams, silicone polymers, and combinations thereof.

It is yet another object of the present invention to provide for the slow release from a dispenser, as above, of trace nutrient compounds.

It is yet another object of the present invention to provide for the slow release of trace nutrients, as above, wherein said trace nutrients include zinc, iron, copper, boron, manganese, molybdenum, magnesium, cobalt, chromium, and selenium.

It is yet another object of the present invention to provide for the slow release from a dispenser, as above, of plant regulants.

It is yet another object of the present invention to provide for the slow release from a dispenser, as above, of a pesticide It is yet another object of the present invention to provide for the controlled release from a dispenser of a herbicide; either in an aquatic environment or upon a terrestrial substrate.

It is yet another object of the present invention to provide for the slow release from a dispenser, as above, wherein said compound can be a plant regulant, a nematicide, a soil insecticide, a cercariacide, a molluscicide, and insect larvicide, and the like.

It is yet a further object of the present invention to provide for a slow release aquatic pesticide, as above, wherein said pesticide destroys various aquatic pests such as mollusks, insect larva, trematode larva, and the like.

It is yet another object of the present invention to provide a slow release plastic dispenser, as above, wherein said pesticide includestrialkyl organotins, Temephos, Malathion, Lindane, Sevin, Rotenone, Dichlovos, and the like.

It is yet another object of the present invention to provide a slow release plastic dispenser, as above, wherein said dispenser releases nematicides or soil insecticides.

It is yet another object of the present invention to provide a slow release nematicide or soil insecticide dispenser, as above, where the nematicide includes Dasanit, Ethoprop, Dichlofenthion, Bromophos, and wherein said soil insecticide includesAldrin, Chlorodane, Carbofuran, Phorate, Terbufos, and the like.

It is a further object of the present invention to provide a slow release plastic dispenser, as above, wherein said porosigen has a solubility in water of less than 0.1 or 0.001 grams per 100 grams of water but usually greater than 0.0005 grams per 100 grams of water.

It is still another object of the present invention to provide a slow release plastic dispenser, as above, containing a porosigen having a solubility of from about 0.1 grams per 100 grams of water to about 100 grams per 100 grams of water.

It is yet a further object of the present invention to provide a slow release plastic dispenser for releasing a pesticide in an aqueous environment, as above, wherein said dispenser floats.

It is yet another object of the present invention to provide a slow release floating dispenser, as above, which may be in any of several forms, such as anchored strands, anchored chips, bimodal or polymodal pellets, and the like.

It is yet another object of the present invention to provide a floating dispenser, as above, so shaped such that it is not covered during release over a period of months by various items such as silt, debris, and the like.

It is yet another o bject of the present invention to provide a floating thermoplastic dispenser, as above, wherein said floating dispenser may be attached to an anchor, as through a connecting member, for example, a line, orthe like.

These and other objects of the present invention will become apparent from the following specification.

In its broadest form therefore the invention is said to reside in a controlled release active compound dispenser comprising; an active compound and a polymer said polymer being in the form of a matrix containing the active compound said polymer being selected from a group consisting of a thermoplastic, a thermoset polymer and combinations thereof.

The dispenser being such that upon contact of the dispenser with the environment the active compound is released at a desired rate.

Generally, a controlled release plant nutrient dispenser, comprises: 100 parts by weight of a polymer matrix, said polymer matrix made from a compound selected from the group consisting of a thermoplastic, a thermoset polymer, and combinations thereof; and a plant nutrient, the amount of plant nutrient ranging from about 10 to about 160 parts by weight per 100 parts of said polymer matrix and being dispersed throughout said polymer matrix so that upon contact of the dispenser with soil moisture, the plant nutrient is released art a rate required by the plant to stimulate growth.

Generally, a process for the controlled release of a plant nutrient from a dispenser, comprises: adding and mixing 100 parts by weight of a polymer, and from about 10 to about 160 parts by weight per 100 parts of said polymer matrix of a plant nutrient, said polymer selected from the group consisting of a thermoplastic, a thermoset polymer, and combinations thereof; forming a polymer matrix containing said plant nutrient contained throughout said matrix, thereby forming a dispenser; and applying and contacting said dispenser with soil so that upon contact with moist soil said plant nutrient will be released at a rate required by the plant to stimulate growth.

Generally, the controlled release of a soil compound from a dispenser, comprises: 100 parts by weight of a polymer matrix; a soil compound, said soil compound dispersed in said polymer matrix, said polymer matrix made from a polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; a porosigen, said porosigen dispersed in said polymer matrix; the amount of said porosigen ranging from about 1 to about 80 parts by weight per 100 parts of polymer, said porosigen having a solubility of less than 100 grams per 100 grams of water, said soil compound selected from the group consisting of a plant regulant, a nematicide, a soil insecticide, and combinations thereof.

Additionally, a process for the controlled release of a soil compound from a dispenser, comprises the steps of: adding and mixing 100 parts by weight of a polymer, from about4 to about 60 parts of a soil compound by weight per 100 parts of said polymer, and from about 5 to about 80 parts of a porosigen by weight per 100 parts of said polymer, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof, said soil compound selected from the group consisting of a plant regulant, a nematicide, a soil insecticide, and combinations thereof, said porosigen having a solubility of less than 100 grams per 100 grams of water; forming a polymer matrix containing said soil compound and said porosigen dispersed throughout said matrix and thereby forming a dispenser; and applying and contacting said dispenser to soil so that upon contact with moist soil, said soil compound is released.

Generally, a floating controlled release pesticide dispenser, comprises: 100 parts by weight of polymer matrix, said polymer of said polymer matrix selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; a pesticide, said pesticide dispersed in said polymer matrix, said pesticide being a pesticide for destroying aquatic pests in an aqueous environment, the amount of said pesticide ranging from about 2 parts by weight to about 80 parts by weight per 100 parts of said polymer except when said pesticide is an organotin compound, the amount of said organotin compound ranging from about 25 parts to about 75 parts; a porosigen, said porosigen dispersed in said polymer matrix, said porosigen slowly releasing said pesticide from said polymer, said dispenser having a density of less than 1.0 grams per cc; and an anchor, said anchor having a density of greaterthan 1.0 grams per cc and connected to said dispenser.

Additionally, a controlled release pesticide dispenser, comprises: a polymer matrix, the amount of said polymer being 100 parts by weight, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; a pesticide, said pesticide dispersed in said polymer matrix, said pesticide being a pesticide for destroying aquatic pests in an aqueous environment, the amount of said pesticide ranging from about 2 parts to about 80 parts by weight per 100 parts of said polymer, except when said pesticide is an organotin compound, the amount of said organotin compound ranging from about 25 to about 75 parts; and a porosigen, said porosigen dispersed in said polymer matrix, said porosigen slowly releasing said pesticide from said polymer, said porosigen having a solubility of 100 grams or less per 100 grams of water.

Generally, a process for the controlled release of a pesticide from a floating dispenser, comprises the steps of: adding and mixing 100 parts by weight of a polymer, from about 2 to about 80 parts by weight per 100 parts of polymer of a pesticide except when said pesticide is an organotin compound, the amount of said organotin compound ranging from about 25 to about 75 parts, and a porosigen, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; forming a floating polymer matrix dispenser, said dispenser having a density of less than 1.0 grams per cc; and attaching said dis penserto an anchor, said anchor having a density of greaterthan 1.0 grams per cc.

Additionally, a process for slowly releasing a pesticide compound from a dispenser comprises the steps of: adding and mixing 100 parts by weight of a polymer, a pesticide for use in an aqueous environment for destroying aquatic pests, and a porosigen having a solubility of 100 grams or less per 100 grams of water, the amount of said pesticide ranging from about2 parts to about 80 parts by weight per 100 parts of said polymer, except wherein said pesticide is an organotin compound, the amount of said organotin compound ranging from about 25 parts to about 75 parts by weight per 100 parts of said polymer; and forming a polymer matrix dispenser so that upon contact with an aqueous environment, said pesticide is slowly released therefrom.

Fig. 1 is an elevational view showing a floating chip attached via a line to a weighted anchor which is resting on the bottom of a body of water; Fig. 2 is an elevational view wherein a floating pesticide dispenser is in the form of strands which are attached to a weighted anchor as in the form of a metal clamp; and Fig. 3 is an elevational view showing a bimodal pellet having an anchor end and a floating end such that said floating end resides above the bottom of a body of water.

The present invention relates to a sustained, controlled, or slow release of a compound upon contact with water from a thermoplastic dispenser or a thermoset dispenser generally containing a porosigen compound, and compounds either for the release of trace nutrients, herbicide, or plant growth regulators, or nematicides, or soil insecticides, or molluscicides, or cercariacides, or aquatic larvicides, upon contact with water, either in an aquatic environment or as in moist soil.

In my prior copending continuing applications, my inventions relate to the sustained release of various pesticides, from a thermoplastic matrix, or dispenser, against such aquatic pests such as mosquito larva, the aquatic larva form of parasites, molluscan hosts of trematode parasites, and the like. Furthermore, my prior specifications set forth the various specific pesticide compounds and the fact that the pesticide could be contained in a thermoplastic matrix which floated, that is, did not sink. Furthermore, my prior invention related to the use of a trace nutrient in the thermoplastic matrix so that upon contact with moisture, such as moisture from soil, the trace nutrient would be released and thereby stimulate plant growth.The exact nature of the various pesticides, various porosigens, as well as the trace nutrients contained within the thermoplastic matrix, as well as the concepts of the invention therein, are set forth in my previous continuing applications which are hereby fully incorporated by reference, with regard to all pertinent and essential matter. It is furthermore noted that all my previous continuing applications are incorporated by reference due to the length of the various specifications, but that various portions thereof will be set forth hereinbelow.

Considering first the thermoplastic polymers, that is polymers which soften and flow when heat andlor pressure is applied (the changes being reversible), they are well known to the art and are readily set forth in various references such as textbooks, journals, various encyclopedias, and the like, as for example, the various thermoplastics set forth in the MODERN PLASTICS ENCYCLOPEDIA, 1979-1980, Vol.56, 10A McGraw-Hill, as well as in other years, and the like, which are hereby fully incorporated by reference. Furthermore, the various properties thereof are well known as are the molecular weight distributions. For example, the number average molecular weight can range from about 10,000 to about 1,000,000, desirably from about 40,000 to about 500,000, and preferably from about 60,000 to about 250,000.Various thermoplastics can be utilized so long as a solid dispenser or plastic matrix is formed. However, it is noted that if a thermoplastic is soluble in water, it is not desired or a part of the present invention since the thermoplastic matrix dispenserwill readily and rapidly degrade and not permit slow release over an extended period of time.

Generally, thermoplastics which can be used include the various following thermoplastics, as well as common copolymers or terpolymers thereof. The various polyolefins containing from 2 to 10 carbon atoms. Specific examples include polyethylene, such as low density and high density polyethylene. Typically, low density polyethylene has a partially (approximately 50 to approximately 60 percent) crystalline solid structure, whereas high density polyethylene typically has over a 90 percent crystalline structure. Polypropylene can also be utilized.

Additionally, various copolymers of ethylene may be utilized such as ethylene-propylene, and copolymers of ethylene and vinyl acetate.

An example of an ethylene-vinyl acetate copolymer includes those wherein the amount by weight of the ethylene units, based upon the total weight of the copolymer, ranges from about 60 percent to about 95 percentwith a range offrom about 80 percent to about 93 percent being preferred. The weight average molecular weight of the copolymer generally ranges from about 40,000 to about 400,000 and preferably from about 75,000 to about 300,000.

Desirably, the copolymer has an ASTM Test &num;D1238 melt flow index of from about 6 to about 12 and preferably from about 7 to about 11 and a Vicat softening point of from about 70 degrees C to about 95 degrees C. Since, apparently, the ethylene repeating units in the copolymer act as a regulator with regard to pore size, higher amounts of the ethylene constituent will resuit in slower release times.

An example of an ethylene-propylene copolymer is those having aweightaverage molecularweight of from about 50,000 to about 250,000 with a preferred range of from about 100,000 to about 200,000.

The percent by weight of the ethylene units can generally vary from about 30 percent to about 80 percent and preferably from about 45 percentto about 75 percent. The melt fiow index of the ethylenepropylene copolymer can generally range from about 15 to about 45, and preferably from about 20 to about 32 according to ASTM Test &num;1238 at 190 degrees, 21600 gm,gm/10 minutes.

Moreover, in order to promote long release duration, it has been found useful, although not necessary to blend the ethylene - vinyl acetate copolymer or the ethylene - propylene copolymer, or combinations thereof, with a polyethylene, especially low density polyethylene (that is, a density of from about 0.90 to 0.94 g/cc), having a melt flow index similar to said ethylene - vinyl acetate copolymer, that is from about 5 to about 14 and, preferably, from about 7 to about 11, and a weight average molecular weight of from about 100,000 to about 400,000. Thus, depending upon the rate of release, various amounts of low density polyethylene may be utilized.Generally, to obtain desirable release rates, the amount of homopolyethylene utilized may range from about 30 percent to about 75 percent and, preferably, from about 40 percent to about 60 percent by weight based upon the total weight of the blend of the ethylene - vinyl acetate copolymer, or the ethylene propylene copolymer, or combinations thereof, and the polyethylene.

Polystyrene can be utilized as well as a family of styrene polymers which includes copolymers of styrene with other vinyl monomers or vinyl substituted aromatics having from 8 to 12 carbon atoms, polymers of derivatives of styrene, and the like.

Thus, poly- alpha - methylstyrene may be utilized.

Another group of thermoplastic polymers is the acrylic polymers with specific examples being polyacrylate, polymethylacrylate, and polymethylmethacrylate. The polyvinyl esters constitute yet another group with a specific example being polyvinylacetate. Still another group is the polyvinyl acetals such as polyvinylbutyral. The phenylene oxide-based thermoplastics can also be used. The various chlorine-containing polymers can be utilized such as polyvinyichioride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylfluoride, polyvinylidenefluoride, and the like. These polymers are used with plastication.

The polyamides or nylons are another group of thermoplastics and include Nylon 6, Nylon 10, Nylon 11, Nylon 12, Nylon 6,6, Nylon 6, 10, and the like.

Polyethers such as polyoxymethylene can be utilized. Another large group of thermoplastic compounds are the polyesters such as polyethylene terephthalate, polybutylene terephthalate, and the like. The polyurethanes constitute yet another group of thermo plastics. As known to those skilled in the art, the polyurethanes can be made from several types of polymers or prepolymers. The cellulose plastics are yet another group with specific examples being "Cellophane" (Registered Trade Mark) and rayon.

Desired thermoplastics include polyethylene, including low density polyethylene and high density polyethylene, copolymers of ethylenevinyl acetate, polypropylene, polybutene, polystyrene, poly - alpha - methyl styrene, polymethylmethalate, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyl, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, a copolymer of ethylene - propylene, polyvinyiidene fluoride, Nylon - 6, Nylon - 6,6, Nylon - 6,10, polyox ymethylene, polyethyleneterephthalate, cellophane, rayon, and combinations thereof. Highly desired polymers include polyamide, polyvinyl acetate, polyurethane, and combinations thereof.

Preferred thermoplastics include polyethylene (including low or high density polyethylene), a copolymer of ethylene - vinyl acetate, polystyrene, polypropylene, polyester, and combinations thereof.

The various plastic compounds generally referred to as thermoset compounds can also be utilized.

Thermoset compounds are generally defined as those which change irreversibly under the influence of heat from a fusible and soluble material into one which is infusible and insoluble through the formation of a covalent crosslinked, thermaliy stable network. The thermoset compounds or resins are furthermore those in which crosslinking occurs simultaneously with the final steps of polymerization, regardless of the amount of heat required in this step. Thus the thermoset, the porosigen, and the compound to be slowly released are thoroughly mixed or dispersed and then heated, whereupon a thermoset matrix is formed. The matrix, if need be, is then reduced to an appropriate size through any conventional method, e.g. a pelletizer, whereupon a suitable dispenser is formed.

Thermoset compounds are well known to those skilled in the art and are set forth in various texts, encyclopedias, journals, etc., such as the MODERN PLASTICS ENCYCLOPEDIA, 1979-1980, Vol. 56, No, 10A, McGraw-Hill, which is hereby fully incorporated by reference. Examples of thermoset compounds include the various phenolic resins, the various amino resins such as melamine and the like. The I unsaturated polyester resins may also be utilized as can the various epoxy resins. Still further, the vari ous urethane foams which are cross-linked may be utilized as can the silicone polymers. Also, the vari ous thermoset polyimides can be used. Generally, specific thermosets which can be used include con ventional and known compounds, such as those set forth in various texts, encyclopedias, and the like.

Naturally, any of the above thermoplastics and thermosets may be utilized including combinations thereof. It is generally desirable to use the low cost compounds. Of the thermosets, the various phenol ics and the various epoxies are preferred.

The various trace elements utilized are generally in the form of salts or oxides, which are readily avail able, desirably low in cost, and are not highly deli quescent. It is noted that the term "salts" includes the various hydrates thereof, that is the mono-, the di-, the tri-, the tetra-, the penta-, the hexa-, the hepta-, etc. Should the salt not exist in the non hydrate form, the most common forms are meant With regard to zinc-containing compounds which may be utilized as trace nutrients, they include the following: zinc sulfate, zinc chloride, zinc carbonate, zinc oxide, zinc phosphate, zinc chlorate, zinc nitrate, the various exist ing hydrates thereof, and the like. Typical copper trace nutrient compounds include copper sulfate, copper carbonate, copper oxide, copper oxychloride, copper nitrate, copper phosphate; vari ous copper complexes such as tetraamines, diamines; the various existing hydrates thereof, and the like. Typical iron trace nutrient compounds include iron chloride, iron sulfate, iron oxide, the var ious existing hydrates thereof, and the like. Typical manganese trace nutrient compounds include manganese oxide, manganese sulfate, manganese chloride, manganese nitrate; the various existing hydrates thereof, and the like. Typical boron trace nutrient compounds include boric acid, sodium biborate; the various hydrates thereof, and the like.

Typical molybdenum trace nutrient compounds include molybdenum oxide, sodium molybdate, potassium molybdate, the various existing hydrates thereof, and the like. Typical cobalt trace nutrient compounds include cobalt sulfate, cobalt chlorate, cobalt nitrate; the various existing hydrates thereof, and the like. Typical selenium trace nutrient compounds include sodium selenate, selenium dioxide, selenium trioxide, selenium disulfide, selenium sulfur oxide, and the like. Typical magnesium compounds include magnesium carbonate, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium oxide, magnesium chloride, magnesium ammonium chloride, magnesium phosphate, magnesium sulfite, the various existing hydrates thereof, and the like.Typical chromium compounds include chromium (II) sulfate, chromium chloride, chloropentammine chromium chloride, the various hydrates thereof, and the like.

Desirably, the amount of trace nutrient released by the polymer dispenser is such to make a plant grow, to stimulate plant or animal growth, and to supplement the environment Thus, exact amount will vary from site to site, soil to soil, crop to crop, animal to animal, and the like. As approximate rule of thumb, the dispenser or mixture can contain from about 1 percent to about 60 percent by weight of a particular trace nutrient ion based upon the total weight of the dispenser, pellet, etc. From about 2 to about 50 percent is desirable, with from about 4 to about 40 percent being more desirable. The amount of trace nutrient generally ranges from about 10 to about 160 parts by weight based upon 100 parts by weight of the polymer, desirably from about 25 to about 125, and preferably from 50 to about 100 parts by weight.

Naturally, more than one trace nutrient may be utilized in the dispenser and thus several may be utilized. Furthermore, since some of the trace nutrients serve as a porosity agent itself, it is not always necessary to utilize a porosigen, although a porosigen is generally preferred, and will hasten the release rate. Trace nutrients, which have a fair degree of solubility, include zinc sulfate, zinc chloride, copper sulfate, copper oxychloride, iron sulfate, iron chloride, manganese sulfate, manganese chloride, boric acid, sodium biborate, sodium molybdate, cobalt sulfate, and sodium selenate.

Controlled release trace nutrients are usually added directly to the soil by conventional application means. Selection is based upon need as well as the particular nature of the soil. For example in alkaline soil needing iron, a choice selection would be an iron salt soluble in the alkaline range, whereas in acid soil, the selection would be a salt soluble in the acid pH range. Since release is dependent upon soil moisture, a hygroscopic material such as calcium chloride which attracts moisture can be utilized as a matrix additive for use in dryer soils. The range of the hygroscopic material is from about one half to about 25 and preferably from about 1 to 5 parts by weight per 100 parts of polymer. Examples of specific hygroscopic compounds include P2Os, Mg(Cl04)2, KOH, Awl203, and Ba (Cl04)2.Also, additives such as lime might be similarly added to the matrix in order to change the soil pH in the immediate vicinity of the dispenser in order to induce more rapid trace nutrient release and plant absorption.

Controlled release trace nutrients are not only of value to crop production, but also to pasturage, forestry, horticulture, and the like, and such uses are hereby implied.

Controlled release trace nutrients may also be added directly to livestock production, such as beef cattle, poultry, sheep, swine, and the like, as an additive to feed.

Pesticides are compounds which kill things undesirableto man, for example, animals, such as insects, and the like. Various pesticides are effective against aquatic pests such as mosquito larva, black fly larva, midge larva, the molluscan hosts of trematode parasites, for example, snails, and some cases the aquatic larva forms of such parasites, and the like. Examples of pesticides which are effective against aquatic animal pests include tetramethyl O,O'-thiodi - p - phenylene phosphorothioate (commonly referred to as Temephos), an organotin compound having the formula R3SnX, wherein R3 is an alkyl group having from 1 to 8 carbon atoms, desirably from 3 to 6 carbon atoms1 and preferably 3 carbon atoms, that is, propyl and the isomers thereof being preferred.An alkyl group having 4 carbon atoms, that is butyl, and the various isomers thereof is highly preferred. Additionally, the organo portion R of the tin toxicant may be an aryl group or a substituted aryl group with the substituted portion being an alkyl or an ester group containing from 1 to 6 carbon atoms. Specific examples of such compounds include phenyl, phenyl acetate, phenyl propionate, phenyl isobutyrate, and the like.

The anion or "X" portion of the organotin compound can be a halogen, an oxide, an alkoxy OR', wherein R' is an alkyl and contains from 1 to 12 carhon atoms, or an

group where R" is an alkyl having from 1 to 12 car bon atoms, such as propionate, butyrate, pentyate, hexylate, and the like, with acetate being preferred.

Of the various anions, the halogens are preferred with fluorine being highly preferred. Thus, tributyltin fluoride is preferred, with tributylin acetate, triphenyltin fluoride, tributyltin oxide, and triphenyl tin acetate being desired compounds.

Another effective pesticide is 2 - (1 - methylethoxy) phenol methylcarbamate, commonly known as Baygon, manufactured by Mobay Chemical Company of Kansas, Missouri, O, 0 - diethyl - 0 - (3, 5, 6 trichloro - 2 - pyridl) phosphorothioate, commonly known as Dursban; and the 0, 0 - dimethyl phosphorodithioate ester of diethyl mercaptosuccinate, commonly known as Malathion. These compounds, along with Temephos, Dibrom and Fenitrothion are preferred.Other examples include Dibrom or Naled (dimethyl -1,2 - dibromo - 2, 2 - dichloroethyl phosphate; Thiodan, i.e., 6,7,8,9, 10, 10a - hexachloro - 1,5, 5a, 6,9, 9a - hexahydro - 6, 9 - methano- 2,4,3 benzodioxathiepen - 3 - oxide; Lindane, that is Gama - 1,2,3,4,5,6 - hexachlorocyclohexane; Sevin, that is 1 - naphthyl methylcarbamate; Propoxur, that is, 2 - (1 - methylethoxy) phenol methylcarbamate; Rotenon, that is, 1,2, 12, 12a - tetrahydro - 2 - isopropenyl - 8,9 - dimethoxy - (1) - benzopyrano -(3,4,6) -furo - (2, 3, 6) (1) - benzopyran - 6 (6aH) one;DDT, that is, dichloro - diphenyltrichloethane; Methoxychlor, that is, 2,2 - bis (p - methoxyphenyl) - 1, 1, 1 - trich- loroethane; Dimilin, that is N -[(4 - chlorophenyl) (amino) (carbonyl)] - 2,6 - difluorobenzamide; Dichlorvis, that is, dimethyl 2,2 - dichlorovinyl phosphate; Fenitrothion, that is, 0,0 - dimethyl, 0 - (3 methyl - 4 - nitrophenyl) phosphorothioate; Fenthion, that is, 0,0 - dimethyl - 0 [3 - methyl - 4 (methylthio) (phenyl)] phosphorothioate; Dimethoate; that is, 0,0 - dimethyl - S - (N - methylcarbomoyl methyl) phosphorodithioate;Methidathion (Suprocide, that is, O, 0 - dimethyl phosphorodithioate, S ester with 4 - (mercaptomethyl) - 2 - methoxy -1,3,4 - thiodiazoline 5 - one; and, Temephos, that is, 0,0,0,' O' - tetramethyl - O, - O - thiodi - p - phenylene phosphorothioate.

Based upon 100 parts of the polymer dispenser, that is the thermoplastic or the thermosetting compound, the amount of the aquatic pesticide ranges from about 2 parts to about 70 or 80 parts by weight, desirably from about 3 parts to about 50 parts, and preferably from about 5 parts to about 20 parts by weight However, when the aquatic pesticide is an organotin compound, the amount is from about 25 to about 75 parts with from about 40 to about 70 parts being preferred.

The dispenser of the present invention with regard to the aquatic pesticide or herbicide may be applied to any aquatic environment such as ponds, lakes, rivers, streams, swamps, waterways, and the like.

However, such bodies of water will often fill up with silt, debris, and the like, thereby covering the dispenser, as in the form of a pellet, granule, orthe like, and thereby adversely affecting release. On the other hand, it can be washed away. Thus, it is desirable to incorporate the thermoplastic or thermosetting dispenser in a floating form connected to an anchor. In such a manner, the dispenser will reside above the bottom of an aquatic body ofwater and effectively operate for the entire life of the dispenser.

The floating dispenser should have a density of less than 1.0 grams per cc, that is a specific gravity less than 1.0. The density can be controlled through proper selection of components including polymers, that is, thermoplastics or thermoset, lightweight fillers, as well as the use of common and conventional blowing agents known to those skilled in the art.

Often, the density of the dispenser will be less than 1.0 grams per cc and thus not require such additives.

Generally, any conventional foaming or blowing agent, as well as lightweight filler may be utilized.

Examples of specific blowing agents well known to the art, include the various known and conventional foaming or blowing agents, as well as those set forth in various texts, journals, encyclopedias, and the like, such as for example those set forth in MODERN PLASTICS ENCYCLOPEDIA, as noted above, which is hereby fully incorporated by reference. The amount of the blowing or foaming agent is simpiy that required in order to make the dispenser float. This is usually a very small amount and may vary from about 0.05 to about 2 parts by weight per 100 parts of polymer, with from about 0.1 to about 1.0 parts being preferred. A suitable blowing agent is Celogen.This blowing agent, as with all other desired blowing agents, degrades by release at a temperature at which the floating pesticide dispenser or composition can be extruded without degrading the components thereof. The gas creates a series of gas filled voids within the matrix. Other blowing agents include Celogen OT, Celogen RA, and the like which release nitrogen and/or carbon dioxide and/or carbon monoxide upon the application of heat thereto. Still other materials include liquids that vaporize at extrusion temperatures such as dichloroethane, or carbon dioxide releasing materials such as various bicarbonates, or nitrogen releasing chemicals such as azodicarbonamide, and N, N'- dinitrosopentamethylenetetramine.

Instead of a foaming or blowing agent, a lightweight filler may be utilized. Again, such lightweight additives are known to the art and include materials such as microballoons (e.g., phenolic), powdered nut shells, corn cob, wood dust, and the like. Once again, the amount required is that such that the dispenser will float. Generally, the amount may vary from about 3 to about 25 parts by weight with preferably from about 5 to about 15 parts by weight per 100 parts of polymer. Furthermore, it is noted that various thermoplastics orthermosets may also be utilized often times without any filler or blowing agent, since they often have a very low density of less than 1.0 grams/cm3, as, for example, low density polyethylene, and other polymers.

In orderto ensure that the floating dispenser is not washed or floated away in various environments, but generally contained in a confined area, it has an anchor. The anchor should be of a weight such as to prevent it from floating away in the intended area of use. Generally, the density of the anchor is in excess of 1.5, desirably in excess of 2.7 grams per cc and the total weight is often in the range of from about 2 to about 10 or 5 to 50 times the total weight of the floating dispenser. Of course, depending upon the actual use situation, the anchor weight may be less than this range or even a specific gravity of 1.5 or 2.7 grams per cc as when utilized in an area of slow moving or stagnant water, for example, a swamp, or in excess of this weight if utilized in an area of fast moving water, for example, a brook, stream, drainage ditch, catch basin, etc.

A specific embodiment of the floating dispenser is disclosed in Fig. 1 wherein the floating dispenseris generally indicated by the numeral 10, with the anchor generally indicated by the numeral 12 which may be in the form of a weight 13. A string, line, or any other suitable connecting means 15 extends and connectsthefloating dispenser or chip and the anchor. The density of the anchor, as noted above, is generally in excess of 1.5 or 2.7 grams per cc and may be an item such as steel, for example, a washer, a metal crimp, generally any other metal, or other item which serves as a suitable ballast. Desirably, the length of line is such as to preclude silting over due to input of various sorts of debris, in the particular aqueous environment.

The floating pesticide dispenser, as shown in Fig.

1,thus resides within the aqueous body and can be made to reside within the infraneustral zone where mosquito larva spend most of their time before emergence, or in the zone where various other aquatic pests such as snails inhabit. Moreover, depending upon the length of connecting line 15, floating pesticide dispenser 10 can be made to always float upon the water surface (not shown) regardless of typical variations in level of the water depth. This factor also affords a visible inspection.

A second structure for suspending a floating controlled release pesticide or herbicide dispenser is in Fig. 2. In this embodiment, floating pesticide dispenser 10, which has a density of less than 1.0 grams per cc, is processed as an extruded strand, rope, or the like. One or more strands 18 are clamped together through fastener 20 which may be a metal crimp or generally any compound having a density of 1.5 or 2.7 grams or greater as well as a mass greater than that of a total number of extending strands 18. Naturally, strands 18 have a length conducive to their end use, and sufficient to avoid coverage as by slit or debris. The crimp is of suitable geometry, e.g., may have tines or legs, to prevent the strands from washing away as through flooding.

Moreover, several strands may be held together as by having an enlarged bottom portion (not shown) so that a mechanical binding occurs at a fastener through which the strands cannot pass. Of course, strands may also be crimped in the center so that one length of strand becomes two strands.

Another structure for a floating release dispenser is shown in Fig. 3. In this Fig., two pellets, granules, etc., are shown. Pellet 31 is a dispenser and it is attached and connected to anchor 33. In this particular drawing, the shape is that of a bimodal pellet, that is two pellets of different densities which have been connected as for example, through heating the pellets to their softening temperature and connecting them together, by melt welding or through the use of adhesives, or any other conventional manner. As apparent from Fig. 3, the bimodal pellet sits above the bottom of a body of water so that any silt, debris, a blocking layerof material, orthe like, as indicated by the numeral 35 does not cover the floating portion of the bimodal pellet.The floating portion has a density of less than 1.0 grams per cc, whereas the anchor portion has a density of from about 1.02 to about 1.1 grams per cc. The net effect is that the system floats on silt, sand, or mud depth increases with increasing deposition. Although a bimodal structure is shown in Fig. 3, multimodal pellets may exist having a plurality of floating dispenser portions as well as a plurality of anchor portions. Moreover, they may exist in various geometric forms or shapes.

As should be apparent from the above embodi ments, generally any type, shape, orform of floating dispenser-anchor arrangement can be utilized within the concepts of the present invention. Moreover, the sizes of the various pellets, strands, anchor, and the like may vary greatly. The connection may be direct as in the bimodal pellet or it may be a connecting line of any suitable material such as a polyester, nylon, fish line, or other water-resistant material.

Naturally, the floating dispenserwill have incorpo rated therein the various components as set forth herein.

The type of porosigen can vary depending upon the desired release rate sought. Thus, a porosigen having a moderate or low solubility can be utilized, that is a solubility of approximately 0.1 grams or less per 100 grams of water with a solubility of approxi mately 0.01 grams or less per 100 grams of water often being desired. The lower limit of solubility is generally that which will give a suitable release rate for a specific application. Such a release rate will vary depending upon the amount of porosigen, the amount and type of compound, e.g., pesticide, the amount of dispenser utilized, and the like, all of which can be readily determined by one skilled in the art. Thus, porosigens can be utilized which are very slightly soluble or barely soluble. Generally, a lower solubility limit of about 0.0005 is desired.Addition ally, a porosigen may be utilized which has a solubility of between 0.1 to about 1 gram per 100 grams of water, or from about 1.0 gram, or about 10 grams to about 100 grams per 100 grams of water. That is, a porosigen may be utilized having a solubility in the range of from about 0.1 to about 100 grams per 100 grams of water, or a sub-range thereof. The porosigen, regardless of solubility, may generally be any compound which is inert with regard to the types of polymer, the trace nutrient, the aquatic pesticide, or the type of release compound incorporated therein. That is, by inert, it is meant that the porosigen does not chemically react with the polymer, trace nutrient, pesticide compound, etc., or otherwise render the dispenser ineffective for its intended purpose. Furthermore, it should not be damaging or harmful to the environment in terms of toxicity.The porosigen can generally be any com pound which is setforth in the Handbook of Chemis try and Physics, 1977-78, published by the Chemical Rubber Company, which is hereby fully incorporated by reference, which meets the above requirements with regard to solubility, inertness, and being non harmful to the environment.

With regard to the low or moderate solubility porosigens, a suitable porosigen includes the inor ganic salts orthe hydrates thereof, or oxides. The cation of such a salt may generally be any of the alkaline metals and preferably any of the non-toxic alkali or alkaline earth metals, Column 1 A and 2A, respectively, of the Periodic Table. Additionally, var ious pious other metals may be utilized such as iron, nic- kel, zinc, tin, silver, and the like. The anion portion of the salt may generally be any negative charge entity, as the various carbonates, the various bicarbonates, the various nitrates, nitrites, or nitrides, the various sulfates, sulfites, or sulfides, the various phosphates, phosphites, or phosphides, including the ortho-, pyro-, hypo-, variations thereof, and the like.Generally, the sulfates, sulfites, and sulfides are preferred as anions, with carbonates being highly preferred.

Moreover, as noted above, the anion may be an oxide of the metal. Specific examples of porosigens include magnesium carbonate, magnesium sulfide, magnesium phosphide, magnesium oxide, calcium carbonate, calcium bicarbonate, calcium nitride, calcium oxide, calcium phosphate, calcium phosphite, calcium sulfide, calcium sulfite, iron carbonate, iron sulfate, iron sulfide, iron sulfite, nickel carbonate, nickel sulfide, zinc carbonate, zinc sulfide, zinc sulfite, tin sulfide, tine oxide, silver carbonate, silver oxide, silver sulfide, silver sulfite, sodium bicarbonate, lithium phosphate, beryllium oxide, strontium carbonate, strontium sulfate, and strontium sulfite.

Magnesium carbonate and strontium carbonate are preferred, with calcium carbonate being highly preferred.

The inorganic salts, or hydrates, or oxides thereof, of the alkali metals and the alkaline earth metals, Column 1A and 2A, respectively, of the Periodic Table, as well as of nickel, iron, zinc, tin, and silver, having a solubility of at least 0.1 grams/1 00 grams of water and up to about 100 grams per 100 grams of water can be used. Desirably, the halogen or carbonate salts of these cations can be used, with the chloride salts being preferred. The Handbook of Chemistry and Physics, 1977-78 Edition, Supra. is hereby fully incorporated as to such specific compounds since the list is rather extensive.Additionally, ammonia as a cation constitutes another class of salts with specific examples being ammonium bromide, ammonium carbonate, ammonium bicarbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, and the like. Of this group, sodium bicarbonate, sodium carbonate, and ammonium sulfate are preferred.

With regard to the amount of porosigen when utilized with the trace nutrients, the range is from 0.1 to about 70 parts by weight based upon 100 parts of the polymer, although up to 100 parts may at times be utilized. If a porosigen is utilized having a solubility of greater than 0.1, that is from about 0.1 to about 100 grams per 100 grams of water, the amount desirably ranges from about 1 to about 30 parts and preferably from about 2 to about 12 parts. If a porosigen has a solubility of less than 0.1 parts or less than 0.01 parts per 100 parts of water, that is down to about 0.0005 grams per 100 grams of polymer, the desired amount ranges from about 5 to about 70 with a preferred amount ranging from about 15 to about 35 parts per 100 parts of the polymer.The porosigens having a porosity of from about 0.1 to about 100 grams per 100 grams of water are generally preferred so that a quicker release of the trace nutrient is obtained.

With regard to the pesticides, the amount of porosigen is as previously set forth; that is, if the porosigen has a solubility of 0.1 or less, for example, to about 0.0005 grams per 100 grams of polymer, the amount ranges from about 15 to about 70 and from about 25 to about 60 for the organotin compound.

For the other pesticides, the range is from about 5 parts to about 70 parts by weight and desirably from about 15 to about 35 parts per 100 parts of polymer.

If a porosigen having a solubility of 0.1 or greater is utilized, the amount of porosigen ranges from about 1 part to about 60 parts, with 2 parts to about 20 parts being desired.

The composition, in addition to the above mentioned compounds, can contain conventional additives to enhance dispersion, add color, aid in processing, or to alter density. Thus, from about 0.2 to about 10 or 20 parts by weight of an insoluble compound such as zinc stearate per 100 parts by weight of the polymer may be utilized as a dispersant. Usually, an amount up to about 5 or 10 parts; and even up to 1 or 2 parts is often used. The ability of the pesticide, including nematicides, plant regulants, etc., or trace nutrient to leave the dispensing unit and pass into the ambient environment wherein dwells the target organism is dependent upon contact with moisture. Said moisture can penetrate said dispenser via movement through a pore structure into said dispenser wherein said pesticide or trace nutrient may be solvated by ingressing moisture and thus move outward through diffusion.Such a system is termed leaching. In orderto create said porosity and thus allow leaching to occur, the porosigen additive must first be solvated and removed as described above. However, in some cases, the pesticide molecule or the trace nutrient molecule may be of too great a physical size to move conveniently from the occupied spaces, or intermolecular voids, between matrix molecules. This volume, termed herein as "free volume", can at times play a critical role in release of the incorporated agent into the growing pore network. It has been discovered that free volume can be altered through the specific incorporation of a secondary polymers Where agent molecule dimensions are large, an increase in free volume improves the rate of agent movement from the interstitial spaces into the water-filled pore.In order to increase free volume and thus improve efficacy, a secondary polymer at melt index, widely variable from the binding, or matrix, polymer is utilized.

For example, if the matrix polymer has a melt index of 1.5, the secondary polymer selected would have a melt index of 6.0 or greater, a disparity of 5 to 25 melt index units being desirable.

According to the concepts of the present invention, the slow release of a compound such as the trace nutrient, the plant regulants, the herbicides, the various pesticide compounds which kill mosquito larva, molluscans, and other aquatic pests, the nematicides and the grub or soil insects, are slowly released from the thermoplastic or thermoset dispenser over a period of time. The mechanism of release depends upon exposure of the porosigen to moisture or water, that is with the dispenser actually residing within a body of water or residing on or in the soil and therefor subject to soil moisture. When contained in the soil, the dispenser is in integral con tact therewith, and the compound is released directly into the soil.Since the porosigen is thoroughly mixed, blended, or dispensed through out the dispenser along with the compound, various portions of the surface of the granule, pellet, etc., that is the dispenser, will contain portions of porosigen. Thus, upon contact with moisture or water, the porosigen will slowly dissolve and, through a dissolution process, creates a porous net work or structure through the thermoset orthermop lastic dispenser. This permits the water to contact the thereby exposed incorporated compound, for example, trace nutrient, plant regulant, pesticide, herbicide, whereby it is actually released; that is, actually drawn out of or removed from the dis penser.This solvation process of the porosigen results in the gradual and controlled release of the compound in the water over a period of time such as from a period of weeks, months or even years.

The compound to be released, be it a plant regul ant, a nematicide, a soil insecticide, herbicide, etc., are insoluble in the plant matrix, but usually slightly soluble in water. Since they are thoroughly mixed or dispersed throughout the disenserwith the polymer matrix, they will not be released in any significant amounts with regard to efficacy, since water cannot penetrate to reach the agent save through the pore network, if they are released at all. However, the dis persment or mixture of the porosigen in the polymer matrix provides a pore structure and thus a suitable slow release mechanism.Moreover, should a particular compound be water soluble and/or a liquid, it is still generally slowly released in a controlled man ner, since it is dispersed throughout the matrix and generally is not mobile except through the pore structure created by the porosigen.

The slow or controlled release dispenser is prepared by mixing, blending, etc., the compound, such as the trace nutrient, the pesticide, the plant regulant, the nematicide, the soil insecticide, the herbicides, with the thermoplastic and the porosigen in suitable proportions as indicated herein in any conventional mixing apparatus along with various additives, such as colorants, dispersants, and the like.

The mixture is coalesced by generally heating it above the softening point and preferably above the melting point of the thermoplastic. The result is a slow release dispenser having a polymer matrix, wherein the pesticide, the herbicides, trace nutrient, etc., is thoroughly mixed or dispersed, for example monolithically dispersed; that is, the compound usually exists as an individual entity or site, throughout the dispenser. Naturally, the porosigen is also mixed or dispersed throughout the dispenser.

The dispenser may be made into any manner, shape, or form. Thus, if the compounds are mixed and extruded from an extruder, they may be in the form of ribbons, or chopped into pellets, chips, or the like.

Naturally, the temperature of the coalescing apparatus relates to the softening or melting point of the thermoplastic and may range from about 170 degreesCto about 190 degrees C, or from about 120 degrees C to about 220 degrees C, although lower or higher temperatures may be utilized depending upon the thermoplastic. Additionally, the dispenser can be prepared by melt casting, solution casting, and the like, such techniques known to the plastic processing art.

Similarly, when a thermoset plastic is utilized, the pesticide, the herbicides, trace nutrient, etc., and the porosigen is mixed, blended, etc., at a temperature below the polymerizating temperature of the ther moset. Then, the mixture, wherein the compound is thoroughly mixed or dispersed, for example, mono lithically, is heated as in an extruded or other con ventional apparatus to produce the dispenser in any suitable size, shape, etc. Should the size not be suit able, etc., the matrix can be cut, chopped, etc., by conventional apparatus to achieve a suitable size, etc.

In a similar manner to the compounds set forth above, other compounds can be incorporated within the plastic dispenser utilizing generally the same techniques, process, incorporation, concepts, and the like, with or without minor modifications well known to those skilled in the art. Such compounds include plant regulants and pesticides, such as nematicides, and soil insecticides. Thus, a compound such as a plant regulant, that is a compound specifically formulated to make a specific portion of the plant grow faster than others, a nematicide, that is a compound for killing nematicides, and soil insecticides, that is a compound for killing insects that live in their larva stage in the soil, can be incorporated in the same polymers, either thermoplastic or thermosetting, generally utilizing the same teachings as set forth above, the same porosigens, and the same preparation techniques.Thus, the plant regulant, nematicide, soil insecticide, may be mixed with the porosigen and the polymer in any conventional mixing apparatus such as an extruder, a banbury mixer, etc., along with various additives such as colorants, and the like, and coalesced and formed into any particular desirable shape or size as a pellet, chip, ribbon, etc., as described above. As should be apparent from all of my prior copending specifications, so long as the porosigen and the compound are incorporated into the polymer matrix with a polymer being coalesced throughout the mixture, a porous type network will be formed and the compound will be released upon contact with water.

Generally, any plant regulantcan be incorporated within the dispenser or matrix including maleic hydrazide; ethrel, (2 - chloroethyl)phosphonic acid; Alor; Polaris; and Triacontanol, CH,(CH,),OH, and the like.

Generally, any nematicide can be used with specific examples including, Dasanit, that is 0,0 diethyl 0 .[4.(methylsulfonyl)phenyl] phosphorothioate; Dichlofenthion,that is, 0,0 - diethyl O - 2,4 - dichlorophenyl phosphorothioate; Bromophos, that is 0,0 - dimethyl 0,2,5 - dichloro - 4 - bromophenyl - phosphorothioate; Ethoprop, that is, 0- ethyl S,S- dipropyl phosphorodithioate, and the like.

Generally, any ground or soil insecticide may be used. By a soil insect, it is meant any insect which has a larva or burrowing stage of life in the soil, for example, Japanese beetles. It is in this ground stage, that is, actually while within the soil, that the insect is destroyed. Specific examples of soil insecticides include Aldrin, that is, hexachlorohexahydro - endo exo - dimethane naphthalene; Dieldrin, that is, hexachloro - epoxy - octahydro - endo - exo dimethanonaphthalene; Chlorodane, that is, octachloro - 4,7 - methanotetrahydro - indane; Temik (Aldicarb), that is, 2 - methyl - 2 - (methylthio) prop ionaldehyde -0 - (methylcarbamoyl) oxime; Carbofuran, that its,2,3 dihydro - 2,2 - dimethyl - 7 - benzofuran methyl carbamate;Landrin, that is, trimethyl phenyl methylcarbamate; Chlorfenvinphos, that is, 2 - chloro - 1 - (2,4 - dichlorophenyl)vinyl diethyl phosphate; Phorate, that is, 0,0 - diethyl - S -[(ethylthio)methyl] phosphorodithioate; Terbufos, that is, S -test - butyl thiomethyl - 0-0- diethyl phosphorodithioate, and the like.

The plant regulants, dispensers of the present invention are utilized by applying them to soil, that is, on top of soil, and desirably by applying them within the soil. Although the nematicides and the soil insecticides can be applied on the soil, since the compound is effective with regard to the stage of life within the soil, it is highly preferred that these compounds contained in the dispenser be added so that they are contained within the soil. The method or manner of addition to the soil is by any conventional means such as by plowing, tilling, banding, cultivating, furrowing, and the like. Thus, the release mechanism occurs from moisture (water) in the soil.

The overall amount of porosigen ranges from about 5 to about 80 parts by weight per 100 parts of polymer. Since the amount of moisture in the soil is not that existing in an aquatic environment, the high solubility porosigens are desired in the dispenser, that is, the porosigens as noted above having a solubility of from about 0.1 up to about 100 grams per 100 grams of water are preferred. The amount of high solubility porosigen ranges from about 1 to about 40 parts by weight per 100 parts of polymer in the dispenser, that is, pellet or the like, with from about 1 to about 30 parts being desired, and 12 to about 25 being preferred. When the low solubility porosigen is utilized, naturally a higher amount of porosigen is desired in order to obtain proper release rates.Generally, the amount of the low solubility porosigen, that is, a porosigen having a solubil ity of less than 0.1 or 0.01 ranges from about 5 to about 70 or 80 parts per 100 parts of polymer, with from about 15 to about 35 parts being preferred. The type and amount of porosigen is the same as that set forth above. That is, the porosigen should be inert with regard to the thermoplastic orthermoset plastic as well as with regard to the plant regulant, etc.

Moreover, it should not be harmful to the environment, that is, the soil and the like.

The amount of plant regulant, nematicide, or ground insecticide which is incorporated into the plastic matrix or dispenser ranges from about 10 to about 160 parts per 100 parts of polymer, desirably from about 15 to about 100, and preferably from about 20 to about 50 parts by weight per 100 parts of polymer. Moreover, as previously noted, from about 1 to about 25 parts of a hygroscopic agent can be utilized to help absorb moisture.

Different trace nutrients and pesticides will release at different rates, dependent upon water solubility, partition coefficient, cohesive energy density, molecular size, and other physical and chemical properties of the agent molecule and the matrix.

Moreover, different amounts of the compound can be varied as well as the amount of porosigen to give a desirable release rate, such that the items, e.g., a pest or a soil insect, is generally controlled; that is, eliminated, killed, kept in check, orthe like.

HERBICIDE COMPOUNDS A herbicide is a chemical substance used to destroy plants. Plants undesirable to man or his environment may be destroyed by the herbicides of the present invention. Herbicides in the composition of the present invention are released at a controlled rate to sustain obstruction of undesirable plant growth over long periods of time. The controlled release herbicide activity is desired for both aquatic and terrestrial environments.

Herbicides to be used in the composition of the present invention depend upon the plant desired to be destroyed. Therefore, the class of herbicides known to those skilled in the art of destroying undesirable plants are compounds within the concepts of the present invention. Representative examples of herbicides known to those skilled in the art are the following available chemicals, expressed in common name and chemical nomenclature in parenthesis:Alachlor (Lasso), 2 - chloro - 2', - 6' - diethyl N - (methoxymethyl) acetanilide; Treflan (Trifluralin), a,a,a, trifluoro - 2,6 - dinitro - N, - N - dipropyl - p - toluidine; Propachlor (Ramrod) 2 - chloro - N - isopropylacetanilide; Basagran (Bentazon) 3 - isopropyl 1 H - 2,1,3 - benzothiadiazin - (4) 3H - one - 2 - dioxide; Metribuzin (Lexone) 4 - amino - 6 - (1,1 dimethylethyl) - 3 - (methylthio) - 1,2,4, - triazin - 5 - (4H) - one; Dicamba (Banvel), 3,6 - dichloro - 0- anisic acid; Glyphosate (Round Up), N - (phosphonomethyl)glycine isopropyl - amine salt of Sutan S - ethyl diisobutylthiocarbamate; Butralin (Amex 820) [4- (1,1 - dimethylethyl) - N - (1. methylpropyl)] - 2,6 - dinitrobenzeneamine;Carbyne (Barban) 4 - chloro - 2 - butynyl - m - chlorocarbanilate; Avådex, S - 2,3 - dichloroallyl diisoprnpylthiocarbamate; Eptam (EPTC), s - ethyl dipropylthiocarbamate; Lorox (Linuron) 3 - (3,4 - dichlorophenyl) - 1 - methoxyl - 1 - methyl - urea; Paraquat (Gramoxono), 1:1 - dimethyl -4,4' - bipyridinium(cation)dichloride; Amiben (Chloramben), 3 - amino - 2,5 - dichlorobenzoic acid; Cotoran (Zanex) (Fluometuron), 1,1 dimethyl - 3 - (2,a,a - trifluoro - m - tolyl) urea; Karmex (Diuron), 3- (3,4 - dichlorophenyl) - 1,1 dimethylurea; Krenite, ammonium ethyl carbamoylphosphate; pronamide (Kerb), 3,5 - dichloro - N - (1,1 - dimethyl - 2 - propyl) - benzamide; Picloram, 4, amino - 3, 5, 6 - trichloro - picolinic acid; Penoxalin (Prowl), N - (1 - ethylpropyl) 3,4- dimethyl - 2,6 dinitro benzeneamine; Propanil (Stam), 3,4 - dichloropropionanalide; Atrazine, 2 - chloro - 4 - ethyl amino - 6 - isopropylamino - S - triazine; 2,4 - D acid, 2,4 - dichlorophenoxy acetic acid; Fenac, 2,3,6trichlorophenylacetic acid; Bromacil, 5 - bromo - 3 sec. - butyl - 6 - methyluracil; Simazine (Princep), 2 - chloro - 4,6 - bis(ethylamino) - S - triazine; Diquat, 6,7 - dihydro - dipyrido(1,2a'2'1' - c)pyrazidinium dib romide;Dichlobenil (Casoron), 2,6 - dichloroben- zonitrile; Dacthal, dimethyl tetrachloroterephthalate; Machete (Butachlor), 2 - chloro - 2,6 - diethyl - N (butoxymethyl)acetanilide; Surflan, 3,5 - dinitro - N,N - dipropylsulfanilamide; Tolban (Profluralin), N(cyclopropylmethyl) - a,a,a, - trifluoro - 2 - dinitro N - propyl - p - toluidine; 2,4 - D amine (Decamine), dimethylamine salt of 2,4 - dichlorophenoxyacetic acid; 2,4 - D ester (Weedone LV4), isooctyl ester of 2,4 - dichlorophenoxy acetic acid.

Of these herbicides, the following are desired: Alachlor, Treflan, Dicamba, Glyphosate, Diuron, Carbyne, Pronamide, Penoxalin, 2,4 - D acid, Fenac, Bromacil, Atrazine, Simazine, Diquat, Dichlobenil, 2,4- D amine, 2,4 - D isooctly ester, and the butoxyethanol ester.

Of these herbicides, the following are preferred: Treflan, Glyphosate, Diuron, Pronamide, Fenac, Bromacii, Diquat Alachlor, Dichlobenil, 2,4 - D D amine and 2,4 - D isooctyl ester.

These herbicides function to destroy a variety of undesirable plants, even in the presence of crops for human or animal consumption. For example, (the following) Table I indicates herbicides representative of the list above and the crops they protect.

TABLE I Agent, Usage and Manufacturers Agent Manufacturers Type Crops Diruon DuPont et al Pre- & post-emergence Cotton, fruits, nuts, oatssugar cane, wheat, citrus, alfalfa, sorghum (also non crop areas) Simazine Ciga-Geiby Pre-emergency Alfalfa, orchards, citrus, corn, grapes, grasses (sod), nuts, sugar, olives Diquat ICI (Chevron-U.S.) Pre-harvest dessicant Cotton, potato, clover, soy beans, sugar cane Fenac Tenneco, Amchem Noncrop areas Pre-emergence Sugar cane Bromacil DuPont ---- Non-crop areas Pre-emergence Sugar cane Atrazine Ciga-Geigy Pre- & ost-emergence Corn, pasture, sugar cane, sorghum, forest, turf grass Dichlobenil Thompson-Hayward - Nuts, fruits, berries, alfalfa, ornamentals 2,4- D acid Thompson-Hayward Post-emergence Fruits, grains, grass, rice + ester Rhodia, Amchem pastures, sorghum, wheat, + amine Dow etc. sugar cane Treflan Elanco Pre-emergence alfalfa, cabbage, carrots, celery, citrus, cherries, corn, beans, nuts: sugar, what Glyphosate Monsanto Post-emergence small grains, corn, soybeans, orchards, vineyards, rubber, palms, coconut, cocoa, coffee, tea" bananas Pronamide Rohm & Haas Pre-emergence alfalfa, lettuce, clover, turf early post-emergence Alachlor Monsanto Co. Pre-emergence soybeans,corn, cotton, potatoes, and peanuts Herbicides are needed for destruction of undesired plants in both the aquatic and terrestrial environments. Again,the herbicides to be used may be adaptable to aquatic or terrestrial environments according to the chemical activity of the herbicide.

This information is known or readily discernible to a person skilled in the art. For example, all of the herbicides listed above can be terrestrial herbicides and the following herbicides can be used as well in aquatic environments: Diuron; Simazine; Diquat; Fenac; Bromacil; Atrazine; Dichlobenil; 2,4 - D acid; 2,4 - D amine; and 2,4 - D isooctyl ester.

In the concentration of the herbicide or combinations of herbicides in the controlled release compound of the present invention can range from about 10 partsto about 160 parts byweight per 100 parts of polymer: Desirably, the concentration of the herbicide or herbicides may range from about 15 parts to about 100 parts by weight per 100 parts of polymer.

Preferably, the concentration of the herbicide or herbicides may range from about 20 parts to about 50 parts by weight per 100 parts of polymer. With any of these concentrations, it is remembered that the rate of dispersal of herbicide, its effective concentration at a given point in time, is dependent upon the concentration of the porosigen and the porosity rate.

Therefore, these concentration ranges represent the total potential concentration of herbicide over the duration of controlled release.

The concentration of the porosigens described above for use in the controlled release composition having herbicides ranges from about 1 part to about 70 or 80 parts by weight per 100 parts of polymers This concentration is applicable to the low or moderate solubility porosigens and the higher solubility porosigens.

For the low or moderate solubility porosigens, it is desired to have a concentration from about 5 parts to about 70 or 80 parts by weight per 100 parts of polymer. Preferably, this porosigen group ranges in concentration from about 15 to about 35 parts by weight per 100 parts of polymer.

For the higher solubility porosigens, it is desired to have a concentration from about 1 to about 40 parts by weight per 100 parts of polymer. Preferably, this porosigen group ranges in concentration from about 1 part to about 30 parts by weight per 100 parts of polymer. Optimally, the range of porosigen concentration varies from about 12 parts to about 25 parts by weight per 100 parts of polymer.

TERRESTIAL DISPENSER METHODS The herbicide dispensers of the present invention are utilized by applying them to soil, that is, on top of soil, and desirably by applying them within the soil.

The method or manner of addition to the soil is by any conventional means such as by plowing, tilling, banding, cultivating, furrowing, and the like. Thus, the release mechanism occurs from moisture or water in the soil. Depending upon the type of undesired plant and the area of the plant most susceptible to attack, by toxins, the choice between using a low or moderate solubility porosigen or a higher solubility porosigen is determined by individual factors.

Generally, since the amount of moisture in the soil is not that existing in an aquatic environment, the higher solubility porosigens are desired in the dispenser, that is, those porosigens as noted above having a solubility of from about 0.1 up to about 100 grams per 100 grams of water are preferred. As expressed above, the porosigens should be inert with regard to the thermoplastic orthermoset plastic as well as with regard to the herbicide. Moreover, it should not be harmful to the environment.

Since controlled release is dependent upon soil moisture, a hygroscopic material such as calcium chloride which attracts moisture can be utilized as a matrix additive for use in dryer soils. The range of the hygroscopic material is from about one half to about 25 and preferably from about 1 to 5 parts by weight per 100 parts of polymer. Other examples of specific hygroscopic compounds include P2O, Mg(CIO4)2, KOH, Al203, and Ba ((C104)2.

Different herbicides will release at different rates, dependent upon water solubility, partition coefficient, cohesive energy density, molecular size, and other physical and chemical properties of the agent molecule and the matrix.

Moreover, different amounts of the compound can be varied as well as the amount of porosigen to give a desirable release rate, such that the undesired plant, is generally controlled; that is, eliminated, kiiled, kept in check, or the like.

POROSIGEN MODIFYING AGENTS In addition to the porosigens of the present invention, the controlled release composition may contain porosity modifying constituents. These constituents may be combined with the porosigens to provide a multi-stage creation of the pore structure, hygroscopic attraction, inducement of porosity or other complementary features. For example, inert liquids compatible with the dispersible in the polymer such as lower aliphatic and glycols may be utilized. The glycols, which are highly water soluble, often will activate the porosigen by permitting more rapid water ingress and thus faster contact between a porosigen, such as CaCO3 or (NH4)2SO4 and water.

Another porosity constituent is soy oil, or other organic compounds similar in properties. Soy oil tends to be water insoluble and thus blocks or inhibits pore formation. Soy oil is preferred, and this constituent may be added in an amount from about 2 to about 25 and desirably from about 2 parts to about 6 parts by weight per 100 parts of polymer.

Another porosity constituent is silicon dioxide.

This constituent, which is low water solubility, can be used to inhibit or slow down the growth of a pore network arising from the loss of a porosigen by water contact and solvation. This constituent may be added in an amount from about 2 parts to about 25 parts by weight per 100 parts of polymer. These other porosity constituents are not necessary for the creation of the controlled release compositions, but they may be added to complement the functions of the porosigens.

TRACE NUTRIENTS To further illustrate the scope of the invention, zinc sulfate releasing dispensers were prepared in accordance with the recipes provided in Table II. Said recipes were mixed, extruded at 250"F to 350"F, cooled, and pelletized or solvent cast and pelletized at room temperature. Pellets of each recipe were then immersed in demineralized water and zinc ion release periodically noted. Analyses were performed by removing an aliquot of water and determining the zinc content in accordance with the Zincon method as detailed in WATER ANALYSIS, Hach Chemical Co., Ames, lowa page 2-149, 1975.

Note that compounds prepared had incorporated therein either no porosigen or a "fast" porosigen ammonium sulfate, solubility70.6g/100g water at 20 degrees C; or a "slow" porosigen, calcium carbonate, solubility 0.001 5g/1 00g water at 25 C.

Table Ill thus indicates the respective loss of zinc ion from compounds.

TABLE II Controlled Release Zinc Recipes INGREDIENT (Weight by Percent) COMPOUND CODE LDPE HDPE EVA PP4 PES5 ZST6 CaCO3 (NH4)SO4 ZnSO4 1A 64 - - - - 1 15 - 20 18 64 - - - - 1 - 15 20 1C 79 - - - - 1 - - 20 2A - 64 - - - 1 15 - 20 28 - 64 - - - 1 - 15 20 2C - 79 1 - - 1 - - 20 3A - - 64 1 - 1 15 - 20 38 - - 64 - - 1 - 15 20 3C - - 79 1 - 1 - - 20 4A - - - 64 - 1 15 - 20 4B - - - 64 - 1 - 15 20 4C - - - 79 - 1 - - 20 5A - - - - 64 1 15 - 20 58 - - - - 64 1 - 15 20 5C - - - - 79 1 - - 20 Low density polyethylene, Complex 10238, Complex Co., Rolling Meadows, Illinois Extruded at 350 F.

High density polyethylene, Chemplex 6001, Chemplex Co., Extruded at 350 F.

Ethylene vinyl acetate copolymer, Complex 3315, Chemplex Co. (28% VA copolymer) Extruded at 250 F.

Polypropylene, P-460) Honatech Inc., Yonkers, N.Y.; Extruded at 300 F.

5Polyester, Hytrel, E.l. DuPont Chemical Co., Wilmington, Delaware. Extruded at 350 -400 F.

Zinc Stearate (dispersant).

TABLE II(continued) INGREDIENT COMPOUND (Weight by Percent) CODE PAM7 PS8 EP9 ZST CaCO3 (NH4)sSO4 ZnSO4 6A 65 - - - 15 - 20 68 65 - - - - 15 20 6C 80 - - - - - 20 7A - 64 - 1 15 - 20 7B - 64 - 1 - 15 20 7C - 79 - 1 - - 20 8A - - 65 - 15 - 20 8B - - 65 - - 15 20 8C - - 80 - - - 20 7 Polyamide, Elvamide 8061, E.I. DuPont de Nemours and Co.., Wilmington, Delaware Solution cast in ethyl alcohol.

Polystyrene, P-400; Honatech, Inc., Yonkers, N.Y.Extrudec@at 400 F.

Epoxy, polyester-styrene based, Dynatron Bondo Corp., Atlanta, Georgia.

Heat, self-generated.

TABLE III Release Rate Zinc Sulfate in Demineralized Water COMPOUND PERCENT RELEASEDIDA Y IMMERSED CODE POROSIGEN 30-day period' 70-day period2 REMARKS 1A slow 0.31% 0.31% 18 fast 1.66% - Release complete in 60 days 1C none 0.12% 0.05% No release after31 days 2A slow 0.32% 0.20% 28 fast 0.55% 2C none 0.05% 0.02% No release after 8 days 3A slow . 0.35% 0.15% 38 fast 1.37% - Release complete in 72 days 3C none 0.05% 0.02% No release after7 days 4A slow 0.35% 0.19% 48 fast 0.80% - Release complete in 40 days 4C none 0.29% 0.14% 5A slow 0.35% 0.16% 58 fast 0.39% 0.35% 5C none 0.09% 0.07% 6A slow 0.63% 68 fast 2.49% 6C none 1.00% 7A slow 0.39% 0.23% 78 fast 1.02% 0.47% 7C none 0.08% 0.06% 8A slow 5.5% 88 fast 1.3% 8C none 5.1% The period covered is from immersion day 2, through immersion day 31. The initial 24-hour release is discounted in that agent on the pellet surface and not monolithically incorporated is rapidly solvated and lost.

2 The period covered is from immersion day 2 through immersion day 71.

* Period of release was 7 days.

To further illustrate the invention, consider compounds 3A, 38, and 3C. Table IV provides greater detail as tao loss in water.

TABLE Zinc Sulfate Loss From Ethylene VinylAcetate Copolymer ACCUMULATED PERCENT LOSS OF ZINC ION COMPOUND POROSIGEN 24hrs. 7days 31 days 40days 71 days 3A slow 7.25% 11.3 % 12.5 % 12.5 % 12.7 % 3B fast 68.25% 88.95% 100 % - 3C none 3.25% 4.85% 4.85% 4.85% 4.85% Obviously, 3C, lacking porosigen, stopped emitting zinc after surface washing was completed.

Further illustration of the phenomenon is seen with elastomeric materials. Table V provides the recipes for compounds RA, RB and RC based on natural rubber. Table VI depicts loss rates.

TABLE V R Recipes INGREDIENT (by parts) COMPOUND Natural Rubber1 CaC03 (NH4)2SO4 ZINC SULFA TE CODE Compound RA 100 15 - 15 RB 100 - 15 15 RC 100 - - 15 TABLE VI Zinc Loss From Natural Rubber Compounds %ACCUMULATED LOSS COMPOUND POROSIGEN iday 7 days 31 days 77 days RA fast 4.4% 5.4% 5.7% 5.7% RB slow 0.0% 0.3% 0.3% 0.3% RC none 0.0% 0.0% 0.0% 0.0% As can be akewed, zinc sulfate is not released from an elastomer, and even with the use of a highly soluble porosigen, only a slight amount is released, all within a few days.

NOTE: The natural rubber compound master recipe is: Natural Rubber 100 parts Stearic acid 0.2 parts Carbon black 10 parts Alfax 2.0 parts ZnO 2 parts Sulfur 2.5 parts Phenyl-ss-naphthylamine 1 part EXAMPLE II Tributyltin Fluoride (TBTF) Recipes TABLE VII Ingredients (Weight Percent) COMPOUND CODE LDPE HDPE EVA CaCO3 (NH4)2SO4 ZnSt TBTF PS 1A 64 - - 15 - 1 20 18 64 - - - 15 1 20 1C 79 - - - - 1 20 2A - 64 - 15 - 1 20 - 28 - 64 - - 15 1 20 - 2C - 79 - - - 1 20 - 3A - - 64 15 - 1 20 - 38 - - 64 - 15 1 20 - 3C - - 79 - - 1 20 - 4A - - - 15 - 1 20 64 48 - - - - 15 1 20 64 4C - - 1 - - 1 20 79 The compounds were made identical to those set forth in Example I, except that 20 parts of tributyltin fluoride (TBTF) was used instead of 20 parts of ZnSO4.

Where tested against Glabrata snails, the following results were observed.

TABLE VII Controlled Release TBTF Bioassayed Against B. Glabrata Snails (30 day bioassay-0.66 ppm -ta') MORTALITY TIME COMPOUND INDAYS CODE POROSIGEN LT50 LT90 18 Fast 13 23 27 1C None 16 30+ 28 Fast 10 11 12 2C None 16 25 30+ 3A Slow 15 22 28 38 Fast 8 10 11 3C None 30+ - 4A Slow 15 18 23 48 Fast 7 9 10 4C None - 30+ The dosage used was 0.66 ppm total active agent, i.e., if all the agent were released at once, it would be the TBTF concentration in the water. In reality, life is over 2 years for each material the water concentration would never exceed about 0.001 ppm/day.

NOTE - LT = lethal time LT50 = time (days) to 50% snail mortality LT50 = time (days) to 90% snail mortality LT100 = time (days) to 100% snail mortality Each bioassay was replicated 3 times with 10 healthy adult snails per replicate. Aquarias contained 100ml of conditioned water.

EXAMPLE III INSECTICIDE RELEASE Various insecticidal agents were incorporated in a number of polymeric matrices in a manner described in Example I and evaluated against mosquito larva. Examples are provided for Temephos, Naled (dibrom), Sevin and Fenitrothion.

Bioassays were performed against Culex Pipiens larva, at 1 ppm total active agent dosage (i.e., 1 ppm is the total amount of agent in the plastic dispensing pellet, and not the water concentration). Pellets were prewashed 24 hours prior to testing to remove some of the surface accumulation of the agent TABLE IX Insecticide Recipes INGREDIENT BY WEIGHT PERCENT COM POUND TEME- FENI CODE LDPE HDPE EVA PHOS TROTHION NALED CaCO3 (NH4)2SO4 ZST PP PES PAM PVAC PS U 11A - 74 - 10 - - 15 - 1 - - - - - 11B - 74 - 10 - - - 15 1 - - - - - 11C - 89 - 10 - - - - 1 - - - - - 12A - - 74 10 - - 15 - 1 - - - - - 12B - - 74 10 - - - 15 1 - - - - - 12C - - 89 10 - - - - 1 - - - - - 13A - - - 10 - - 15 - 1 - 74 - - - 13B - - - 10 - - - 15 1 - 74 - - - 13C - - - 10 - - - - 1 - 89 - - - 14A - - - 10 - - 15 - - - - - 75 - 14B - - - 10 - - - 15 - - - - 75 - 14C - - - 10 - - - - - - - - 90 - 15A - - - 10 - - 15 - 1 - - - - 74 15B - - - 10 - - - 15 1 - - - - 74 15C - - - 10 - - - - 1 - - - - 89 16A - - - 10 - - 15 - - - - - - - 75 16B - - - 10 - - - 15 - - - - - - 75 16C - - - 10 - - - - - - - - - - 90 17A - - - - 10 - 15 - 1 - - - - 74 17B - - - - 10 - - 15 1 - - - - 74 17C - - - - 10 - - - 1 - - - - 89 18A - - - - 10 15 - 1 - - - - - 18B - - - - 10 - 15 1 - - - - - 18C - - - - 10 - - 1 - - - - - 19A - 74 - - - 10 15 - 1 - - - - - 19B - 74 - - - 10 - 15 1 - - - - - 19C - 89 - - - 10 - - 1 - - - - - 20A - - - - - 10 15 - 1 74 - - - - 20B - - - - - 10 - 15 1 74 - - - - 20C - - - - - 10 - - 1 89 - - - - - TABLE IX Insecticide Recipes Continued INGREDIENT BY WEIGHT COM POUND TEME- FENI CODE LDPE HDPE EVA PHOS THROTHION NALED CaCO3 (NH4)2SO4 ZST PP PES PAM PVAC PS U 21A - - - - - 10 15 - - - - 75 - - 21B - - - - - 10 - 15 - - - 75 - - 21C - - - - - 10 - - - - - 90 - - 22A - - - - - 10 15 - 1 - - - - 74 22B - - - - - 10 - 15 1 - - - - 74 22C - - - - - 10 - - 1 - - - - 89 Polyvinyl acetate, Ayac, Union Carbide Chemicals Co., Cleveland, Ohio.

Solution cast in acetone.

Polyurethane, 5701F1, B.F. Goodrich Chemical Co., Cleveland, Ohio.

Solution cast in tetrahydrofuran.

TABLE X Mosquito Larva Bioassay (2nd Instar C. pipiens pipiens) COM POUND PERCENT MOSQUITO MORTALITY BY DAYS CODE AGENT POROSIGEN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 11A Temephos slow 7 37 73 73 83 100 - - - - - - - 11B Temephos fast 27 70 87 100 - - - - - - - - - 11C Temephos none 0 27 37 40 40 47 53 57 60 67 70 * - 12A Temephos slow 0 9 30 33 60 63 70 70 73 * - - - 12B Temephos fast 15 43 47 93 100 - - - - - - - - 12C Temephos none 7 14 17 20 27 33 40 100 - - - - - 13A Temephos slow 0 7 13 30 43 53 67 73 100 - - - - 13B Temephos fast 21 63 77 83 100 - - - - - - - - 13C Temephos none 0 3 7 17 23 23 37 37 37 40 40 40 43 * 14A Temephos slow 0 13 17 17 17 23 30 40 43 57 67 90 90 93 14B Temephos fast 10 17 23 27 43 97 100 - - - - - - 14C Temephos none 0 0 3 13 13 13 17 27 33 47 57 * - - 15A Temephos slow - - - - - - - - - - - - - 15B Temephos fast 23 37 50 63 67 67 83 100 - - - - - 15C Temephos none 0 10 13 17 17 17 20 40 40 * - - - 16A Temephos slow - - - - - - - - - - - - - 16B Temephos fast 17 17 97 97 100 - - - - - - - - 16C Temephos none 10 13 13 13 17 27 30 30 33 * - - - 17A Fenitrothion slow - - - - - - - - - - - - - 17B Fenitrothion fast 47 50 - - - - - - - - - - - 17C Fenitrothion none 0 3 - - - - - - - - - - - 18A Naled slow 30 43 53 57 73 73 * - - - - - - 18B Naled fast 50 100 - - - - - - - - - - - 18C Naled none 33 40 40 40 * - - - - - - - - 19A Naled slow - - - - - - - - - - - - - 19B Naled fast 30 33 33 43 53 67 77 83 - - - - - 19C Naled none 17 20 20 33 40 40 40 43 - - - - - 20A Naled slow - - - - - - - - - - - - - 20B Naled fast 30 43 47 50 53 57 63 70 - - - - - 20C Naled none 0 7 7 7 7 * - - - - - - - 21A Naled slow 20 20 27 27 27 * - - - - - - - 21B Naled fast 10 13 30 37 43 70 - - - - - - - 21C Naled none 0 13 13 27 30 30 * - - - - - - 22A Naled slow - - - - - - - - - - - - - 22B Naled fast 23 73 100 - - - - - - - - - - 22C Naled none 10 10 20 23 30 33 33 33 - - - - - Control Naled - 0 0 0 7 10 13 20 27 37 * - - - * = pupation and adult emergence occurs EXAMPLE 4 To further illustrate the long term agent release incident to the controlled release material, the formation of Table Xl immersed in water and said water periodically analyzed for agent concentration. Said analysis allows the computation of a release rate.

Table XII illustrates this data. Since the loss rate is known (60 days) and the amount of agent incorporated in said formulation, a release life projection can be derived.

TA BLE XI RECIPES EXAMPLE LDPE EVA TEMEPHOS ZnSt CaCO3 (NH4J2SO4 23A 74 - 10 1 15 23B 74 - 10 1 - 15 23C 89 - 10 1 - TABLEXII Release Rate and Extrapolated Lifetime of Controlled Release Temephos RELEASE RA TE RELEASE Microgramsigram- LIFE EXAMPLE POROSIGEN liter-day (years) 23A CaCO3 8.0 48.0 23B (NH4)2SO4 15.9 12.4 23C none 2.0 ineffective EXAMPLE 5 The ethanolamine salt of niclosamide was dispensed in several thermoplastic matrices, extruded at 190 F, pelletized and evaluated againstBiomp hlada glabrata snails at various dosages. Table XIII depicts the recipes used and Table XIV, the bioassay results. It is noted thatthese finely tuned recipes depend upon an increase in free volume created by the use of polymer alloys of low density polyethylene (MN718) & ethylene-propylene copolymer (Vistalon 702). The porosigen system is a mix of a low water solubility porosigenic agent and a high watersolubility agent.

TA BLE XIII Ethanolamine Niclosamide Recipes Example INGREDIENT 26 27 28 Vistalon702 33 27 25 MN 718 33 27 25 Zinc Stearate 1.2 1 1 Niclosamide 12.5 30 30 CaCO3 12.5 5 13 (NH4)2SO4 8 10 7 TABLEXIV Bioassay: Controlled Release Ethanolamine Niclosamide Versus B. glabrata Snails (30-Day Evaluation DOSAGE EXAMPLE (totalactiveJ LT, LOTS, LTtoo 26 5 ppm 15 24 1 ppm 16 28 0.5 ppm 20 - 27 5 ppm 20 - 1 ppm 20 - 0.5 ppm 20 - 28 5 ppm 2 3 10 1 ppm 20 22 25 0.5 ppm 20 22 25 NOTE: Wherein the ratio of CaCO3: (NH4j2SO4 is 5:10 resulting kill rate is very slow, however, at a CaCO3: (NH4)2SO4 ratio of 13:7, an LT100 is achieved within 10 to 25 days depending on dosage.

EXAMPLE 6 Soil Insecticides and Nematicides Various materials such as N,N-dimethyl dodecanamide (NNDD), a nematicide, chloropyrifos andturbophos,soil insecticides, have been prepared as controlled release materials and applied to soil.

Table XV illustrates several chloropyrifos recipes and Table XVI shows release rate in soil.

TABLEXV Chloropipifos Recipes (In a soil insecticide recipe) EXAMPLE EVA LDPE ZnSt (NH4)2SO4 CHLOROPYRIFOS 29 50 40 1 10 15 30 50 40 1 10 8 31 100 - 1 10 20 32 100 - 1 10 10 RESULTS: After ten weeks soil exposure TABLEXVI % CHLOROPIPIFOS LOSS Example PER WEEK 29 4.54.8% 30 5.7-6.1% 3'I 4.9-5.1% 32 3.8-4.0% Examples of Terrestrial and aquatic use for herbicides follow: While in accordance with the patent statutes, the preferred embodiments of the invention have been described in detail, for the true scope of the inven tion, reference should be had to the appended claims.

EXAMPLES For a variety of undesired aquatic plant types, the following table illustrates aquatic weeds good for study.

TABLEXVII COMMON NA ME * BIOLOGICAL NAME TYPE Elodea(EI Elodea canadensis submerged, floating may root, usually not Vallisneria (.V) Vallisneria americana rooted bottom, grass Cabomba (C) Cabomba caroliniana submerged, floating Eurasian Myriaphyllum spicatum submerged, floating Watermilfoil (M) usually does not root Water hyacinth Eichomia crassipes surface floating weed Southern Naiad Najas guadalupensis submerged, floating Alligator weed Altemanthera philoxeroides reed Water lettuce Pistia stratiotes - surface floating weed Duckweed (D) Lemna minor surface floating weed * parenthetical symbols to be used in bioassay data below.

In preparation of the aquatic weed studies, the fol lowing polymer compounds were available for mix15 ing according to the preferred production methods for the thermoplastic polymers, as seen in Table XVIII.

TABLE XVIII Matrix Elements POLYMER TYPE SOURCE LDPE Chemplex 1023B Chemplex (low density polyethylene) MN718 U.S. Industrial Chemical MN710 U.S. Industrial Chemical MN703 U.S. Industrial Chemical HDPE Chemplex 6001 Chemplex (high density polyethylene) EVA Chemplex 3315 Chemplex (ethylvinyl acetate) copolymer PP P460 Hanotech (polypropylene) PS P400 Hanotech (polystyrene) Polyester Hytril DuPont Polyamide Elvamide 6001 DuPont Polyvinyl acetate Ayac 5710 Union Carbide Urethane Estone 5701 F1 B. F. Goodrich Ethylene-propylene Vistalon 702 Exxon Chemical Co.

copolymer In orderto fully illustrate the nature of the invention, a number of examples are provided. Recipes are given along with bioassay data. Data has been accumulated in regard to aquatic weeds. The formulations used consisted of the herbicide agent incorporated into a polymer matrix or a polymer alloy, i.e., wherein two polymers of divergent melt indices are uniformly mixed in the molten state so as to adjust free volume as described above. Various porosigens are likewise incorporated in the matrix in such a manner as to evaluate said porosigen alone or in combination thereof. A higher solubility or "fast" porosigen such as ammonium sulfate, and optionally with a porosity constituent such as ethylene glycol, normally provides a rapid herbicide emission.A low or moderate solubility or "slow" porosigen such as calcium carbonate, and optionally with a porosity constituent such as silicon dioxide, normally provides the slow development of a pore network and thus slow herbicide emission. By combining a "fast" and a "slow" porosigen and respective porosity constituents, release characteristics are suitably altered so that a desired rate may be obtained. The ability to tailorthe given compound to a given or desired herbicide emission rate is especially important for use in a terrestrial soil envoronment wherein said soils vary in moisture content and the physiochemical properties that govern the transport and adsorption of xenobiotics such as herbicides.

EXAMPLE 1- DIURON COMPOUNDS The following Table XIX lists the several recipes for controlled release diuron formulations.

TABLE XIX DIURON RECIPES INGREDIENT {Weight Percent) CODEMIN 718 VISTALON 702 ZINC STEARATEDIURON CaCO3 (NH4)SO4 SiO2 ETHYLENE GLYCOL 1A 29.0 29.0 1 31.0 - 10 - 1B 29.0 29.0 1 31.0 5 5 - 1C 29.0 29.0 1 31.0 5 - 5 1D 28.0 28.0 1 21.0 10 - - 2 1E 28.0 28.0 1 31.0 5 5 - 2 1F 24.5 24.5 1 31.0 5 6 4 4 1G 24.5 24.5 1 31.0 10 4 5 1H 24.0 24.0 1 31.0 10 10 - The Diuron compounds from the above table were bioassayed against select aquatic weeds and select terrestrial weeds. The aquatic bioassays were performed by adding a measured pellet dosage of 10 ppm and 1 ppm to 1 gallon glass aquaria, said aquaria containing 1 gallon of demineralized water and three test plants potted in soil.Each evaluation, i.e., each formulation at each dosage was replicated five times against each aquatic plant. Plants were in part laboratory grown using techniques common to the art and outdoor grown (mil foil). Plants were examined daily for mortality.

Average mortality was computed by averaging the mortality of each group of replicates. Results for the plants in Table XVII are provided in the following Table XX.

TABLE Diuron Bioassay : Aquatic Plants Plant Mortality (accum. %) by day number DOSAGE CODE (ppm) PLANT 5 10 15 20 25 30 40 50 1A 1 E 3 5 21 45 65 88 100 1A 10 E 0 5 18 27 55 57 80 90 1A 1 V 0 0 2 5 10 18 50 60 1A 10 V 0 0 2 7 20 40 83 97 1A 1 C 3 5 26 43 60 77 100 1A 10 C 3 15 85 95 97 100 - 1A 1 M 5 5 17 23 - - - - 1A 10 M 17 27 57 90 100 - - 1B 1 E 0 0 3 13 27 30 100 - 1B 10 E 7 27 73 80 83 86 100 18 1 V 5 10 15 23 30 42 63 76 18 10 V 5 5 11 17 37 55 87 94 18 1 C 5 15 22 25 50 94 100 18 10 C 3 15 71 100 - - - 1B 1 M 5 10 20 35 - - - 18 10 M 17 27 43 93 - - - 7C 1 E 0 0 0 3 3 7 50 60 1C 10 E 3 7 23 37 47 75 95 99 1C 1 V 0 3 7 17 25 34 67 75 1C 10 V 7 10 23 35 50 64 85 90 1C 1 C 0 3 15 22 35 60 100 1C 10 C 0 0 40 93 100 - - 1C 1 M 3 5 7 60 - - - 1C 10 M 17 40 67 93 100 - - 1D 1 E 0 0 15 15 17 32 77 95 1D 10 E 3 7 51 65 80 100 - 1D 1 V 0 5 19 27 35 55 77 90 1D 10 V 7 13 27 40 65 65 85 96 1D 1 C 3 20 50 50 53 88 97 100 1D 10 C 17 60 100 - - - - 1D 1 M 0 0 0 10 - - - 1D 10 M 13 17 27 90 - - - 1E 1 E 0 0 5 17 27 49 95 95 1E 10 E 0 5 13 25 45 67 100 1E 1 V 0 0 2 3 3 8 80 87 1E 10 V 3 5 10 10 27 36 60 70 1E 1 C 5 17 32 43 95 100 - 1E 10 C 0 27 81 93 95 100 - 1E 1 M 0 3 10 13 - - - 1E 10 M 25 43 85 100 - - - 1F 1 E 3 5 34 43 55 76 93 97 1F 10 E 0 7 42 53 75 98 100 1F 1 V 0 3 10 15 17 28 83 90 1F 10 V 0 3 28 50 65 65 80 90 1F 1 C 0 5 22 30 37 75 100 1F 10 C 5 35 85 100 - - - 1F 1 M 5 15 17 37 - - - 1F 10 M 17 45 73 100 - - - 1G 1 E 3 13 37 47 65 84 95 95 1G 10 E 5 17 54 67 77 80 95 95 1G 1 V 0 0 5 7 13 20 73 75 1G 10 V 5 5 25 47 63 70 75 85 1G 1 C 5 10 23 33 47 88 100 1G 10 C 0 13 60 80 100 - - 1G 1 M 0 7 -7 20 - - - 1G 10 M 53 77 87 97 100 - - 1H 1 E 3 13 20 35 35 54 70 90 1H 10 E 10 23 45 60 85 100 - 1H 1 V 0 0 2 3 0 0 13 17 1H 10 V 3 3 5 10 15 22 75 83 1H 1 C 0 5 16 33 63 85 100 1H 10 C 0 3 53 97 100 - - 1K 1 M 0 0 0 5 - - - - 1H 10 M 10 23 27 27 - - - Examination of the Diruon data indicates that release rate is a property of the porosigen utilized.

As can be seen, formulation 1A utilizing the "fast" porosigen, 10 percent ammonium sulfate, shows the most rapid plant destruction. When the total porosigen content is kept at 10 percent but now altered to consist of 5 percent (NH4)25O4 and 5 per- cent CaCO3, a "slow" porosigen, the loss rate, as measured by bioassay, decreases (formulation 1 B).

Now mixing CaCO3 and ethylene glycol (formulation D), the latter being a porosity activating constituent, the loss rate shows a slight decrease. Using a "slow" porosigen and a "slow" porosity mocifying constituent (formulation 1C), a further decrease in loss rate, as measured by bioassay, is seen. Varying the CaCO3 and (NH4)2S04 ratio, as in formulation 1 G, compared to formulation 1 B, also varies the loss rate.

Diuron compounds have been evaluated against terrestrial weeds common to a farm plot in Northeastern Ohio. Pelletized material was broadcast on plowed test sites at rates normal to agricultural usage. Periodic measurements were made evaluating total weed content and dandelion content, in the latter case the weed being planted by broadcasting of seed, whereas in the former weeds being voluntary, comprising mainly ragweed, golden rod, barnyard grasses, buckhorn, dandelion and various other unidentified dicots and monocots. Results are indicated in the following tables.

TABLEXXI Total Weed ContentlSquare Foot byDays A VERA GE WEED HEIGHT CODE DOSAGE 15 26 34 44 AFTER 44 DAYS 1 D 5&num;/acre 19.4 8.0 7.2 13.2 4 inch 1D 20&num;/acre 11.8 3.4 3.0 2.4 3 inch Control 0 39 30 34 50+ 13 inch 1F 5&num;/acre 10.2 9.4 8.6 10.4 4 inch 1F 20&num;acre 10.0 2.2 0.8 2.8 2 inch Control 0 46 24.4 52 50+ 12 inch 1H 5&num;/acre 11.6 8.8 8.4 11.2 6 inch 1H 20&num;/acre 10.2 6.4 7.8 14.2 5 inch Control 0 29 19.8 21.4 50+ 13 inch TA BLE XXII DANDELION CONTENT/100 SOUARE FEET CODE DOSAGE 26 days 34 days 44 days 1D 5&num;/acre 0 2 2 1D 20&num;;/acre 0 5 9 Control 0 15 14 * 1F 5&num;/acre 0 1 16 1F 20&num;/acre 0 0 2 Control 0 12 20 1H 5&num;/acre 6 6 0 1H 20&num;/acre 6 9 0 Control 0 14 13 * * Dandelion shaded out by other broadleaf weeds.

It is readily apparent that weed population and weed height is greatly controlled by the controlled release compositions shown above.

EXAMPLE 2 Controlled release formulations having 2,4 - D acid, as shown in the following table were examined against various aquatic weeds using the techniques described under Example 1. Bioassay data is repeated below.

TABLE XXII 2,4-D ACID RECIPIES Ingredients (Weight Percent) CODE %HERBICIDE VISTALON 702 MN-718 ZnSt CaCo3 SiO2 As EG 2A 25 74 - 1 - - - - 2B 25 - 74 1 - - - - 2C 25 32 32 1 - - 10 2D 25 32 32 1 5 - 5 - 2E 25 32 32 1 5 5 - 2F 25 31 31 1 10 - - 2 2G 25 31 31 1 5 - 5 2 2H 25 27.5 27.5 1 5 4 6 4 21 25 27.5 27.5 1 10 5 4 - 2J 25 27 27 1 10 - 10 TABLE XXIV 2,4-D ACID BIOASSAY:AQUATIC PLANTS Mortality (Accumulative Percent) By Day DOSAGE CODE (ppm) PLANT 4 10 15 20 25 30 35 42 2A 1 E 0 0 5 7 5 5 10 10 2A 10 E 0 0 Q 0 0 0 0 0 2A 1 M 0 10 13 15 0 0 0 0 2A 10 M 0 45 57 57 0 0 0 0 2B 1 E 0 0 0 0 0 0 5 5 2B 10 E 0 5 5 5 0 0 0 0 2B 1 V 3 3 3 3 0 0 3 10 2B 10 V 13 10 10 10 7 7 20 30 2C 1 V 25 37 45 65 75 75 75 80 2C 10 V 15 17 17 33 40 60 63 73 2C 1 C 0 13 17 60 63 65 75 77 2C 10 C 0 13 17 30 70 77 83 83 2C 1 M 15 37 53 73 0 0 0 0 2C 10 M 20 55 63 77 0 0 0 0 2D 1 V 33 33 45 50 63 63 63 63 2D 10 V 20 13 25 37 53 63 73 85 2D 1 C 0 7 7 10 10 13 20 40 2D 10 C 5 5 13 17 50 53 57 60 2D 1 M 3 15 23 25 0 0 0 0 2D 10 M 35 67 70 77 0 0 0 0 2E 1 C 5 7 13 25 40 45 47 47 2G 10 C 10 23 45 100 0 0 0 0 2E 1 E 7 7 7 7 5 5 5 5 2E 10 E 3 5 5 5 7 7 7 7 2E 1 V 20 30 40 50 53 63 70 70 2E 10 V 27 30 33 47 50 60 77 83 2E 1 C 0 0 3 20 53 53 53 53 2E 10 C 0 7 13 27 57 57 60 73 2E 1 M 5 23 33 63 0 0 0 0 2E 10 M 7 17 20 30 0 0 0 0 2F 1 E 0 0 0 0 0 0 0 0 2F 10 E 7 15 45 70 70 70 70 70 2F 1 V 10 13 15 15 3 3 3 3 2F 10 V 15 35 50 75 77 80 80 80 2F 1 C 3 3 10 43 87 93 95 97 2F 10 C 3 5 5 10 50 50 55 90 2F 1 M 0 15 23 33 0 0 0 0 2F 10 M 10 35 60 75 0 0 0 0 2G 1 E 0 3 3 3 3 5 7 7 2G 10 E 3 53 70 100 0 0 0 0 2G 1 V 7 5 10 10 7 17 50 53 2G 10 V 13 25 27 40 37 45 50 53 2G 1 C 5 7 13 25 40 45 47 47 2G 10 C 10 23 45 100 0 0 0 0 TABLEXXlV (continuedJ 2,4DACID BIOASSAY:: AQUA TIC PLANTS -Mortality (Accumulative Percent) By Day Dosage Code (ppm) Plant 4 10 15 20 25 30 35 42 2H 1 E 0 3 5 10 20 20 20 20 2H - 10 E 3 10 25 45 50 50 43 47 2H 1 V 3 17 13 27 47 50 60 65 2H 10 V 13 17 25 33 77 80 80 80 2H 1 C 7 5 17 25 35 40 40 40 2H 10 C 15 20 33 67 80 85 97 100 2H 1 M 0 30 45 63 0 0 0 0 2H 10 M 5 37 45 67 0 0 0 0 21 1 E 0 0 0 7 10 10 7 7 21 10 E 7 7 10 15 20 20 20 17 21 1 V 10 15 23 27 5 5 13 15 21 10 V 10 10 10 10 10 0 0 0 21 1 C 0 0 0 7 25 30 40 40 21 10 C 5 25 30 43 43 47 53 53 21 1 M 10 33 40 45 0 0 0 0 21 10 M 25 43 63 70 0 0 0 0 2J 1 E 0 3 3 7 0 0 0 0 2J 10 E 3 43 60 85 77 77 85 90 2J 1 V 10 5 10 15 15 17 17 20 2J 10 V 3 15 25 30 55 40 40 35 2J 1 C 5 7 13 33 37 45 45 45 2J 10 C 7 20 60 90 100 0 0 0 2J 1 M 10 15 15 20 0 0 0 0 2J 10 M 15 47 67 73 0 0 0 0 Analysis of the bioassay data indicates that where no porosigen is present, formulations 2A and 28, plant kill is minimal (due solely to wash off at the herbicide molecules on or near the dispenser surface), in turn indicating very low or no release of said herbicide. Again, data evaluation shows that compound 2C containing a fast porosigen offers substantially faster plant destruction than compound 2D additionally containing a slow porosigen. Compound 2F, additionally containing ethylene glycol, a porosity activator, is significantly faster in herbicidal action compared to compound 2E having a slow porosigen and a comparable porosity modifying constituent.

2,4-D acid compounds were also evaluated against terrestrial weeds in the fashion described under Example 1. Results are shown in the following table.

TABLEXXV Total Weed ContentlSquare foot By Days Dosage Average Weed Height Code (ppm) 26 34 44 After44 days 2F 2&num;acre 7.2 15.8 23.2 7 inch 2F 10&num;/acre 21.2 6.8 12.2 6 inch Control 0 18.6 14.6 50+ 13 inch 2H 2&num;/acre 2.0 12.8 21.2 7 inch 2H 10&num;acre 17.6 8.4 4.2 6 inch Control 0 014.8 10.0 50+ 10 inch 2J 2&num;acre 5.4 9.6 18.0 6 inch 2J 10&num;/acre 12.4 9.9 12.8 5 inch Control 0 14.2 7.0 5.0 10 inch TABLE XXVI Dandelion Content/100 Square Feet Code Dosage 26 days 34 days 44days 2F 2&num;acre 14 30 50 2F 10&num;acre 11 20 43 Control 0 16 32 * 2H 2&num;/acre 6 10 16 2H 10,&num;/acre 1 3 25 Control 0 14 17 * 2J 2&num;;/acre 14 23 32 2J 10&num;acre 9 9 20 Control 0 13 30 * Again, the tables above readily indicate the improvements of undesirable plant control shown by the controlled release compositions.

EXAMPLES Diquat, a well recognized aquatic herbicide was similarly evaluated against select aquatic weeds.

Unlike the other herbicidal agents evaluated, Diquat is highly water soluble and thus exhibits both the properties of a porosigen as well as the properties of a herbicide. The following tables depict the formulations examined and bioassay data.

TABLEXXVII Diquat Recipes Percent Ingredients Vistalion Code Herbicide 702 MN-718 ZnSt CaCOs S102 As EG 3A 25 74 - 1 - - - - 38 25 - 74 1 - - - - 3C 25 32 32 1 - - 10 - 3D 25 32 32 1 5 - 5 - 3E 25 32 32 1 5 5 - - 3F 25 31 31 1 10 - - 2 3G 25 31 31 1 5 - 5 2 3H 25 27.5 27.5 1 5 4 6 4 31 25 27.5 27.5 1 10 5 4 3J 25 27 27 1 10 - 10 - TABLEXXVIII Diquat Bioassays:Aquatic Plants Mortality {accumulative %) By Day Dosage Code (ppm) Plant 4 10 15 20 25 30 3A 1 E 30 90 100 - - - 3A 10 E 25 85 100 - - - 3A 1 V 3 27 73 97 100 - 3A 10 V 0 43 97 100 - - 3A 1 C 0 25 35 40 60 100 3A 10 C 0 15 25 35 60 100 3A 1 M 50 65 67 73 - - 3A 10 M 73 77 83 85 - - 3B 1 E 5 83 93 100 - - 3B 10 E 45 95 100 - - - 3B 1 V 5 63 75 100 - - 3B 10 V 10 70 97 100 - - 3B 1 C 0 10 10 17 25 - 3B 10 C 0 17 43 80 100 - 3B 1 M 30 35 37 45 - - 3B 10 M 63 77 75 75 - - 3C 1 E 23 93 100 - - 3C 10 E 25 100 - - - - 3C 1 V 3 7 25 63 95 100 3C 10 V 0 20 77 97 100 3C 1 C 0 7 20 25 35 3C 10 C 3 7 27 50 70 3C 1 M 30 47 75 93 - 3C 10 M 67 73 83 87 - - 3D 1 E 13 63 75 100 - - 3D 10 E 13 75 95 100 - - 3D 1 V 3 7 25 63 95 100 3D 10 V 0 20 77 97 100 3D 1 C 0 13 25 33 37 - 3D 10 C 7 35 50 80 97 - 3D 1 M 33 60 65 75 - - 3D 10 M 57 85 90 93 - - 3E 1 E 13 80 100 - - - 3E 10 E 20 77 100 - - - 3E 1 V 3 30 73 100 - - 3E 10 V 0 75 97 100 - - 3E 1 C 0 17 45 65 73 - - 3E 10 C 0 20 47 80 97 - - 3E 1 M 5 20 37 77 - - 3E 10 M 65 75 80 80 - - 3F 1 E 15 85 100 - - - 3F 10 E 17 85 100 - - - 3F 1 V 0 37 83 100 - - 3F 10 V 0 80 100 - - - 3F 1 C 10 50 77 93 100 3F 10 C 3 35 75 100 - - 3F 1 M 57 65 75 100 - - 3F 10 M 83 87 87 93 - - 3G 1 E 0 67 100 - - 3G 10 E 3 87 100 - - - 3G 1 V 3 20 70 97 100 - 3G 10 V 10 55 100 - - - 3G 1 C 0 5 40 47 60 - 3G 10 C 10 50 75 95 100 - 3G 1 M 37 57 83 97 100 - 3G 10 M 55 73 83 97 100 3H 1 E 45 93 100 - - - 3H 10 E 53 93 100 - - - 3H 1 V 5 47 80 100 - - 3H 10 V 5 45 93 100 - - TABLE XXVIII (continued) Diquat Bioassays: Aquatic Plants Mortality (accumulative %) By Day Dosage Code /(ppm) Plant 4 10 15 20 25 30 3H 1 C 0 30 83 100 - 3H 10 C tO 80 100 - - - 3H 1 M - 35 83 93 100 - 3H 10 M - 80 87 93 97 100 31 1 E 20 97 100 - - 31 10 E 45 95 10O - - 31 1 V 0 20 50 80 100 31 10 V 3 47 83 100 - 31 1 C 30 37 63 80 90 31 10 C 3 47 85 97 100 31 1 M 43 85 100 - - 31 10 M 77 97 97 97 100 3J 1 E 5 100 3J 10 E 10 10a ~ ~ ~ ~ 3J t V 0 10 63 83 100 3J 10 V 5 27 67 95 100 3J 1 C 0 25 47 57 70 3J 10 C 10 60 87 93 100 3J 1 M 33 50 80 97 100 3J 10 M 67 83 90 100 - - Due to the highly water soluble nature of Diquat, it is readily emitted without benefit of porosigen. Thus, the porosigen free formulation 3A and 3B kill rapidly In turn, this rapid loss is not favorable becausethe emission life is greatly retarded. In contrast to all other materials, the presence of a porosigen slows herbicide emission. Thus, the controlled emission rate is obtained. 3C containing ammonium sulfate, a fast porosigen, acts at a slower rate against the various plants; than the porosigen free material.The loss rate observed is still slower for compound 3E with a Iower water solubiliuty; porosigen and porosity modifying constituent EXAMPLE 4 In a similarfashion, Atrazine compounds were prepared in accordance with the recipes of the following table: Said compounds were evaluated against aquatic plants using tehniques described under Example 1. Results ofsaid evaluation are presented below.

TABLE XXIX ATRAZINE-RECIPES Ingredient (weight percent) CODE %HERBICIDE VISTALON 702 MN-718 ZnSt CaCo3 SiO2 As EG; 4A 31.30 - 67J 1 - - - - 4B 31 29 29 1 - - 10 - 4C 31 29 29 1 5 - 5 - 4D 31 29 29 1 5 5 - - 4E 31 28 28 1 10 - - 2 4F 31 28 28 1 5 - 5 2 4G 31 24.5 24.5 1 5 4 6 4 4H 31 24.5 24.5 1 10 5 4 - 41 31 24.5 24 1 10 - 10 TABLEXXX A TRAZINE BIOASSA YS:AQUA TIC PLANTS Mortality (accumulative %) By Day DOSAGE CODE (ppm) PLANT 4 10 15 20 25 30 35 42 4A 1 E 0 0 0 0 0 0 0 0 4A 10 E 0 0 0 7 7 10 17 20 4B 1 V 3 7 7 7 0 10 25 37 4B 10 V 20 27 33 55 75 80 87 100 4B 1 C 5 5 20 45 75 75 75 87 4B 10 C 7 7 7 37 63 65 77 100 4C 1 V 15 23 45 65 67 73 73 85 4C 10 V 33 40 40 40 30 63 80 85 4C 1 C 5 10 20 73 90 93 95 100 4C 10 C 0 10 25 55 75 75 75 97 4D 1 E 0 0 0 13 10 10 10 5 4D 10 E 3 3 3 5 3 17 30 35 4D 1 V 7 13 13 17 3 3 17 60 4D 10 V 7 13 27 45 73 75 90 100 4D 1 C 3 5 33 75 93 90 97 100 4D 10 C 10 25 50 73 87 90 95 100 4E 1 C 0 0 0 0 7 37 57 73 4E 10 C 0 0 0 0 10 37 45 75 4F 1 V 10 10 23 40 30 45 57 73 4F 10 V 13 17 23 30 37 50 55 60 4F 1 C 0 0 0 3 0 0 17 60 4F 10 C 0 0 0 3 0 17 30 70 4G 1 V 0 0 0 3 10 13 15 15 4G 10 V 0 5 15 27 47 53 65 73 4G 1 C 0 3 5 13 20 23 33 50 4G 10 C 0 0 0 0 3 20 30 70 4H 1 E 0 3 3 3 37 40 40 40 4H 10 V 0 0 0 3 10 10 15 27 4H 1 C 10 10 15 15 33 47 73 90 4H 10 C 3 3 3 3 57 63 70 70 41 1 C 0 0 0 0 43 43 47 55 41 10 C 3 7 10 20 30 55 57 60 Results indicate that release of the herbicide occurs; and again those formulations containing a fast porosigen, e.g., 4B, release at a more efficacious rate than those with no porosigen, 4A, or a slow porosigen, for example 4G and 41.

EXAMPLE 5 FENAC COMPOUNDS Fenac formulations were prepared in accordance with the following recipes and bioassayed against Elodea and Milfoil. Test methods were as described in Example 1.

TABLEXXXI ZINC ETHYLENE CODE FENAC M-718 EPM STEARATE CaCo3 SiO2 (NH4)2SO4 GLYCOL 5A 5 - 94 1 - - SB 5 94 - 1 - - - 5C 5 . 42 42 1 - - 10 5D 5 42 42 1 5 5 5 5E 5 42 42 1 5 5 5F 5 41 41 1 10 - - 2 5G 5 41 41 1 5 - 5 2 5H 5 37.5 37.5 1 5 4 6 4 51 5 37.5 37.5 1 10 5 4 5J 5 37.5 37.5 1 10 - 10 LT50 (lethal time to 50 percent plant mortality) values are given in the next table.

TABLE XXXII Fenac Compounds: Bioassay with Elodea Canadensis and Eurasian Watermilfoil (Myriophyllum SpicatumJ 37-Day (Evaluation) LTso DOSAGE CODE (ppm) ELODEA WATERMILFOIL 5A 1 not achieved* not achieved* 5B 1 not achieved* not achieved* 10 not achieved* not achieved* 5C 1 28 days 18 days 10 18 days 13 days 5D 1 33 days not achieved* 10 24 days 14 days 5E 1 34 days 35 days 10 34 days 33 days 5F 1 34 days 32 days 10 28 days 18 days 5G 1 35 days 29 days 10 29 days 8 days 5H 1 not achieved* not achieved 10 27 days 11 days 51 1 . 37 days . 21 days 10 29 days 16 days 5J 1 not achieved* 25 days 10 28 days 7 days * release istoo slow for effective plant destruction Again, examination of the data indicates that compounds 5A and 5B, having no porosigen content are ineffectual whereas compounds 5C and 5G, having a fast porosigen present show rapid kill, and compounds 5E, containing a slow porosigen, shows a slow destruction of the test plant.

EXAMPLE 6 Similarly, controlled release composition recipes containing Dichlobenil are given below.

TABLE XXXIII Dichlobenil Recipes Ingredients (Weight Percent) %HERBICIDE VISTALON MN-718 CODE (50% W.P.) ZnSt CaCO3 SiO2 AS EG 6D 10 33.5 33.5 1 10 - - 2 6F 10 30 30 1 5 4 6 4 6H 10 29.5 29.5 1 10 - 10 Dichlobenil releasing formulations were evaluated against terrestrial weeds with the results shown below.

TABLE XXIV WeedslSquare Foot at Day No. A VERA GE WEED COMPOUND CONCENTRATION 15 26 34 44 HEIGHT-DAY 44 6D 4&num;acre 30.0 10.8 20.6 13 6 inches 6D 12&num;/acre 3.8 2.6 3.6 5.2 4 inches Control 0 23.8 12.0 41.6 50+ 15 inches 6F 4&num;acre 8.2 9.2 9.4 8.0 5 inches 6F 12&num;/acre 4.8 2.4 2.8 2.0 4 inches Control 0 8.4 9.0 17.4 50+ 16 inches 6H 4&num;/acre 9.8 8.8 5.2 5.2 5 inches 6H 12&num;/acre 2.0 2.2 0.8 2.0 3 inches Control 0 15.4 16.8 43 50+ 13 inches TABLE XXXV Dandenlions/100 Square Foot at Day No.

COMPOUND CONCENTRATION 26 34 44 6D 4&num;acre 0 0 2 6D 12&num;acre 1 1 0 Control 0 11 8 * 6F 4&num;acre 1 1 12 6F 12&num;acre 1 1 2 Control 0 15 14 * 6H 4&num;lacre 1 1 0 6H 12&num;acre 3 3 0 Control 0 30 8 * * dandelion obscured by ragweed and other weeds EXAMPLE 7 Various Bromacil recipes were prepared in accordance with the following recipes. These were evaluated against several aquatic plants using the method described under Example 1.

TABLE XXXVI BROMACIL RECIPES Ingredients(Weight PErcent) CODE %HERBICIDE VISTALON 702 MN-718 ZnSt CaCO3 SiO2 As EG 7A 31 29 29 1 - - 10 7B 31 29 29 1 5 - 5 - 7C 31 29 29 1 5 5 - 7D 31 28 28 1 10 - - 2 7E 31 28 28 1 5 5 5 2 7F 31 24.5 24.5 1 5 4 6 4 7G 31 24.5 24.5 1 10 5 4 7H 31 24 24 1 10 - 10 TABLE XXXVII Bromacil Bioassay Results (35-day Test Period) DOSAGE CODE (ppm) PLANT LTso (days) 7A 1 E 35 days 10 E 31 days 1 M 35+days* 10 M 15 7B 1 E 15 days 10 E 27 days 7C 1 E 35+ days* 10 E 30 days 10 M 19 days 7D 1 E 35+ days* 10 E 30 days 1 M 23 days 10 M 17 days 7E 1 E 27 days 10 E 18 days 10 M 8 days 7F -1 E 35 days 10 E 26 days 10 M 10 days 7G 1 E 35+ days 10 E 35+ days* 1 M 21 days 10 M 21 days 7H 1 E 34days 1 M 30 days 10 M 15 days * indicates that the LT50 is over35 days Undesirable plant destriction is achieved, as seen above.

EXAMPLE 8 Fenac was incorporated in a polymer alloy in accordance with the recipes shown below.

TABLE XXXVIII INGREDIENT (Code 8A) Percentby Weight LDPE (MN-718) 24 EVA (MU-763) 24 Zinc Stereate 1 CaCO3 24 Fenac 24 Bioassay was performed against several aquatic weeds with the LT50 values shown below.

TABLEXXXIX PELLET DOSAGE LT50(BY DAYS) CODE (ppm) E C D 8A 2 * * 23 5 21 * 24 10 15 22 * * Test not performed

Claims

1. A controlled release active compound dispenser comprising; an active compound and a polymer said polymer being in the form of a matrix containing the active compound said polymer being selected from a group consisting of a thermoplastic, a thermoset polymer and combinations thereof, the dispenser being such that upon contact of the dispenser with the environment the active compound is released at a desired rate.

2. The controlled release active compound dis penseras in Claim 1 wherein the active compound is selected from a group consisting of a plant nutrient, a herbicide, a pesticide, an nematicide, a soil compound, a plant regulant, a plant stimulant or combinationsthereof.

3. A controlled release plant nutrient dispenser, comprising: a plant nutrient, and 100 parts by weight of a polymer, said polymer in the form of a matrix and containing said plant nutrient, said polymer from the group consisting of a thermoplastic, a thermoset polymer, and combinations thereof; the amount of plant nutrient ranging from 10 to 160 parts by weight per 100 parts of said polymer matrix so that upon contact of the dispenser with soil moisture, the plant nutrient is released at a rate required by the plant to stimulate growth.

4. A controlled release plant nutrient dispenser according to Claim 3, wherein said plant nutrient is selected from the group consisting of zinc, copper, iron, manganese, boron, molybdenum, cobalt, selenium, magnesium, chromium, and combinations thereof, and wherein said thermoplastic polymers are selected from the group consisting of polyolefins made from monomers having from 2 to 10 carbon atoms, polystyrene, substituted polystyrene, the acrylic polymers, the polyvinyl ethers, the polyvinyl acetais, the halogencontaining polymers, the nylons, the polyethers, polyesters, polyurethanes, the cellulose plastics, and combinations thereof, and wherein said thermoset polymers are selected from the group consisting of the phenolics, the epoxies, the amino resins, the unsaturated polyesters, the urethane foams, the silicone polymers, and combinations thereof.

5. A controlled release plant nutrient dispenser according to Claim 4 wherein the amount of said plant nutrient ranges from 25 to 125 parts by weight, and wherein said thermoplastic polymer is selected from the group consisting of polyethylene, including low density polyethylene or high density polyethylene, a copolymer of ethylene-vinyl acetate, polypropylene, polybutene, polystyrene, poly - alpha - methyl styrene, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polyetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon-6, Nylon-6,6, Nylon-6,1 0, polyoxymethylene, polyethyleneterephthalate, cellophane, rayon, a copolymer of ethylene-propylene, and combinations thereof.

6. A controlled release plant nutrient dispenser according to Claim 5, wherein said plant nutrient is a compound selected from the group consisting of zinc sulfate, zinc chloride, zinc carbonate, zinc oxide, zinc phosphate, zinc chlorate, zinc nitrate, the various hydrates of said zinc compounds, copper sul fate, copper carbonate, copper oxide, copper oxych- loride, copper nitrate, copper phosphate, the various hydrates of said copper compounds, iron chloride, iron sulfate, iron oxide, the various hydrates of said iron compounds, manganese oxide, manganese sulfate, manganese chloride, manganese nitrate, the various hydrates of said manganese compounds, boric acid, sodium biborate, the various hydrates of said boron compounds, molybdenum oxide; sodium molybdate, potassium molybdate, the various hydrates of said molybdenum compounds, cobalt sulfate, cobaltchloriate, cobalt nitrate, the various hydrates of said cobalt compounds, sodium selenate, selenium dioxide, selenium trioxide, selenium disuifide, selenium sulfur oxide, magnesium carbonate, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium oxide, magnesium phosphate, magnesium sulfite, and the various hydrates of said magnesium compounds, chromium sulfate, chloropentammine chromium chloride, and combinations thereof.

7. A controlled release plant nutrient dispenser according to Claim 6, wherein said thermoplastic polymer is selected from the group consisting of polyethylene including high density or low density polyethylene, a copolymer of ethylene-vinyl acetate, polystyrene, polypropylene, polyester, and combinations thereof, and wherein said thermoset is selected from the group consisting of a phenolic, an epoxy, and combinations thereof.

8. A controlled release plant nutrient dispenser according to any one of Claims 3,4,5,6, or 7, including a porosigen in said matrix, said porosigen having a solubility of from 0.1 to 100 grams per 100 grams of water, the amount of said porosigen ranging from 0.1 to 70 parts per 100 parts of said polymer.

9. A controlled release plant nutrient dispenser according to Claim 8, wherein the amount of said porosigen ranges from 1 to 70 parts, and wherein said porosigen is selected from the group consisting of halogenated alkaline metals, the halogenated alkaline earth metals, halogenated nickel, halogenated tin, halogenated silver, ammonium bromide, ammonium carbonate, ammonium bicarbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, sodium carbonate, and sodium bicarbonate.

10. Acontrolled release plant nutrient dispenser according to Claim 9, wherein the amount of said porosigen ranges from 1 to 30 parts by weight per 100 parts of polymer.

11. A controlled release plant nutrient dispenser according to Claim 9, wherein said porosigen is selected from the group consisting of ammonium sulfate, ammonium bicarbonate, sodium bicarbonate, sodium carbonate, ammonium chloride, and ammonium chlorate.

12. A controlled release plant nutrient dispenser according to Claim 8, including from 1 to 25 parts by weight per 100 parts of said polymer of a hygroscopic compound.

13. A controlled release plant nutrient dispenser according to any one of Claims 4, 5, or 6, including a porosigen, said porosigen having a solubility of less than 0.1 grams per 100 grams of water and wherein the amount of said porosigen ranges from 5 to 70 parts per 100 parts of said polymer.

14. A controlled release plant nutrient dispenser according to Claim 13, wherein said porosigen is selected from the group consisting of an oxide and a salt, said oxide and salt having a cation selected from the group consisting of the alkaline metals, the alkaline earth metals, iron, zinc, nickel, silver and tin, and said salt having an anion selected from the group consisting of a carbonate, bicarbonate, nitrate, nitrite, nitride, peroxide, phophate, phosphite, phosphide, sulfate, sulfite, sulfide, and said porosigen having a solubility of at less than 0.01 grams per 100 grams of water.

15. Acontrolled release plant nutrient dispenser according to Claim 14, including a porosigen having a solubility of from 0.0005 to 0.01 grams per 100 grams of water.

16. Acontrolled release plant nutrient dispenser according to Claim 13, including from 1 to 25 parts by weight per 100 parts of said polymer of a hygroscopic compound.

17. A controlled release plant nutrient dispenser according to Claim 8, wherein said soil moisture removes said porosigen and creates a pore structure in said dispenser.

18. A controlled release plant nutrient dispenser according to Claim 13, wherein said soil moisture removes said porosigen and creates a pore structure in said dispenser.

19. Acontrolled release plant nutrient dispenser according to Claim 3, further comprising a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

20. A controlled release plant nutrient dispenser according to Claim 8, wherein said matrix further comprises a porosigen modifying agent

21. Aprocessforthecontrolled release of a plant nutrient from a dispenser, comprising; adding and mixing 100 parts by weight of a polymer, and from 10 to 160 parts by weight per 100 parts of said polymer matrix of a plant nutrient said polymer selected from the group consisting of a thermoplastix, a thermoset polymer, and combinations thereof; forming a polymer matrix containing said plant nutrient contained throughout said matrix, thereby forming a dispenser; and applying and contacting said dispenser with soil so that upon contact with moist soil said plant nutrient will be released at a rate required by the plant to stimulate growth.

22. A process according to Claim 21, including the step of adding from 0.1 to 70 parts by weight per 100 parts of said polymer of a porosigen, said porosigen having a solubility of less than 100 grams per 100 grams of water.

23. A process according to either one of Claims 21 or22 further comprising adding a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

24. A process according to Claim 22, creating a pore structure with said porosigen in said matrix upon exposureto water.

25. A process according to Claim 22, further comprising adding a porosigen modifying agent.

26. The controlled release of a soil compound from a dispenser, comprising: a soil compound, a porosigen, and 100 parts by weight of a polymer, said polymer in the form of a matrix and containing said soil compound and said porosigen, said polymer selected from the group consisting of a thermoplatic polymer, a thermoset polymer, and combinations thereof, the amount of said porosigen ranging from 1 to 80 parts by weight per 10(1 parts of polymer, said porosigen having a solubility of less than 100 grams per 100 grams of water;; said soil compound selected from the group consisting of a plant regulant, a namaticide, a soil insecticide, and combinations thereof, the amount of said soil compound being from 10 to 60 parts by weight per 100 parts of polymer and being mixed throughout said polymer matrix so that upon contact of said dispenser with soil moisture, said soil compound is released in a controlled manner.

27. A controlled release dispenser according to Claim 26, wherein said polymer is selected from the group consisting of polyolefins made from monomers having 2 to 10 carbon atoms, polystyrene, substituted polystyrene, the acrylic polymers, the polyvinyl ethers, the polyvinyl acetols, the halogencontaining polymers, the nylons, the polyethers, polyesters, polyurethanes, the cellulose plastics, and combinations thereof, and wherein said thermoset polymers are selected from the group consisting of the phenolics, the epoxies, the amino resins, the unsaturated polyesters, the urethane foams, the silicone polymers, and combinations thereof.

28. A controlled release dispenser according to Claim 27, wherein said polymer is selected from the group consisting of polyethylene including low density polyethylene or high density polyethylene, a copolymer of ethylene- vinyl acetate, a copolymer of ethylene-propylene, polypropylene, polybutene, polystyrene, poly-alpha-methylstyrene, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, plychlorotri fluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon-6, Nylon-6,6, Nylon6,10, polyox ymethylene, polyethyleneterephthalate, cellophane, rayon, and combinations thereof.

29. A controlled release dispenser according to Claim 28, wherein said thermoplastic polymer is selected from the group consisting of polyethylene, polypropylene, polyester, and combinations thereof, and wherein said thermoset is selected from the group consisting of a phenolic, an epoxy, and combinations thereof.

30. A controlled release dispenser according to Claim 28, wherein said dispenser resides within a soil.

31. A controlled release dispenser according to any one of Claims 26,27,28,29 or 30, wherein said porosigen has a solubility of from 0.1 to 100 and exists in the amount of from 1 to 40 parts per 100 parts of said polymer.

32. A controlled release dispenser according to Claim 26, wherein said porosigen having said solubility is selected from the group consisting of halogenated alkaline metals, the halogenated alkaline earth metals, halogenated nickel, halogenated tin, halogenated silver, ammonium bromide, ammonium carbonate, ammonium bicarbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, sodium carbonate, and sodium bicarbonate.

33. A controlled release dispenser according to any one of Claims 31 or 32, wherein said nematicidesare selected from the group consisting of 0,0 diethyl 0-[4- (methylsulfonyl)phenyU phosphorothioate; 0,0- diethyl - 0 - 2,4 - dichlorophenyl phosphorothioate; 0,0- dimethyl - 0,2,5 - dichloro - 4 - bromophenyl - phosphorothioate; O-ethyl S,Sdipropyl phosphorodithioate; and combinations thereof; wherein said plant regulants are selected from the group consisting of maleic hydrazide, (2 chloroethyl)phosphonic acid, Alor, CH,(CH,),OH, Triacontanol, and combinations thereof; wherein said soil insecticides are selected from the group consisting of hexachloro - hexahydro - endo exo - dimethane naphthalene; hexa - chloroepoxy octahydro - endo - exo - dimethanonaphthalene; octachloro - 4,7- methanotetrahydro - indane; 2 methyl -2 - (methylthio) propionaldehyde - 0 (methylcarbamoyl) oxime; 2,3- dihydro - 2,2 dimethyl - 7 - benzofuran methyl carbamate; trimethyl phenyl methylcarbamate; 2- chloro - 1 - (2,4 - dichlorophenyl) vinyl diethyl phosphate; 0,0 diethyl - S - [(ethylthio) methyl] phosphorodithioate; S - test - butylthiomethyl - 0- diethyl phosphorodithioate, and combinations thereof.

34. A controlled release dispenser according to Claim 33, wherein the amount of said soil compound ranges from 1 to 100 parts per 100 parts of said polymer, and wherein the amount of said porosigen ranges from 10 to 30 parts per 100 parts of said polymer.

35. A controlled release dispenser according to any one of Claim 26,27,28,29 or 30, wherein said porosigen has a solubility of less than 0.01 grams per 100 grams of water, and wherein the amount of said porosigen ranges from 5 parts to 80 parts per 100 parts of said polymer.

36. A controlled release dispenser according to Claim 34, wherein the amount of said soil compound ranges from 20 parts to 50 parts by weight.

37. A controlled release dispenser according to Claim 35, wherein said porosigen is selected from the group consisting of magnesium carbonate, calcium carbonate, and strontium carbonate.

38. A controlled release dispenser according to Claim 35, wherein the solubility of said porosigen is greater than 0.0005.

39. A controlled release dispenser according to either one of Claims 31 or 35 including from 1 to 25 parts by weight per 100 parts of said polymer of a hydroscopic agent.

40. The controlled release of a soil compound from a dispenser according to Claim 26, further comprising a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

41. The controlled release of a soil compound from a dispenser according to Claim 26, wherein said porosigen creates a pore structure in said matrix upon exposure to water.

42. The controlled release of a soil compound from a dispenser according to Claim 26, wherein said matrix further comprises a porosigen modifying agent.

43. Aprocessforthecontrolled releaseofa soil compound from a dispenser, comprising the steps of: adding and mixing 100 parts by weight of a polymer, from 4 to 60 parts of a soil compound by weight per 100 parts of said polymer, and from 5 to 80 parts of a porosigen by weight per 100 parts of said polymer, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof, said soil compound selected from the group consisting of a plant regulant, a nematicide, a soil insecticide, and combinations thereof, said porosigen having a solubility of less than 100 grams per 100 grams of water, said soil compound and said porosigen dispersed throughout said matrix, and thereby forming a dispenser; and applying and contacting said dispenser to soil so that upon contact with moist soil, said soil compound is released.

44. A process according to Claim 43, further comprising adding a second polymer having a melt index, said second polymer index having a disparity from said first polymer index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

45. A process according to Claim 43, creating a pore structure with said porosigen in said matrix upon exposure to water.

46. A process according to Claim 43, further comprising adding a porosigen modifying agent.

47. A floating controlled release pesticide dispenser, comprising: a polymer, a pesticide, and a porosigen, said polymer in the form of a matrix and containing said pesticide and porosigen, the amount of said polymer being 100 parts by weight, said polymer of said matrix selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; said pesticide being a pesticide for destroying aquatic pests in an aqueous environment, the amount of said pesticide ranging from 2 parts by weight to 80 parts by weight per 100 parts of said polymer except when said pesticide is an organotin compound, the amount of said organotin compound ranging from 25 to 75 parts; and said porosigen slowly releasing said pesticide from said polymer; said dispenser having a density of less than 1.0 I grams percc; and an anchor, said anchor having a density of greater than 1.0 grams per cc and connected to said dis penser.

48. Afloating controlled release pesticide dis penser according to Claim 47, wherein said thermop lastic polymers are selected from the group consist ing of polyolefins made from monomers having from 2 to 10 carbon atoms, polystyrene, substituted polystyrene, the acrylic polymers, the polyvinyl ethers, the polyvinyl acetals, the halogen-containing polymers, the nylons, the polyethers, polyesters, polyurethanes, the cellulose plastics, and combina tions thereof, and wherein said thermoset polymers are selected from the group consisting of phenolics, the expoxides, the amino resins, the unsaturated polyesters, the urethane foams, the silicone polym ers, and combinations thereof.

49. Afloating controlled release pesticide dis penser according to Claim 48, wherein the porosity of said porosigen is 0.1 grams or less per 100 grams of water, wherein the amount of said porosigen ranges from 5 to 70 parts per 100 parts of polymer except for said organotin compound in which the amount of porosigen ranges from 15 to 5 to 70 parts.

50. Afloating controlled release pesticide dis penser according to Claim 49, wherein said pesticide is selected from the group consisting of tetramethyl 0,0' - thiodi - p - phenylene phosphorothioate; 0,0 diethyl -0 - (3,5,6 - trichloro -2 - pyridyl) phos phorothioate; 0,0 - dimethyl phosphorodithioate ester of diethyl mercaptosuccinate, a compound having the formula R3SnX where R3 is selected from the group consisting of an alkyl group having from 1 to 8 carbon atoms, an aryl group, and a substituted aryl group wherein said substituted group is an alkyl or an ester containing from 1 to 6 carbon atoms;X is selected from the group consisting of a halogen, an oxide, an alkoxy OR' where R' is an alkyl having from 1 to 12 carbon atoms. or an

group where R" is an alkyl having from 1 to 12 carbon atoms; 2 11 - methylethoxy) phenol methylcarbamate; dimethyl - 1,2 - dibromo - 2,2 - dichloroethyl phosphate; 6,7,8,9,1 0,lOa - hexachloro- 1,5,5a,6,9,9a - hexahydro - 6, -methano - 2,4,3 - benzodioxathiepen - 3 - oxide; 1 - naphthyl methylcarbamate; gamma - 1,2,3,4,5,6 - hexachlorocyclohexane; 2 - (1 methylethoxy)phenol methylcarbamate; 1,2,12,1 2a - tetrahydro - 2 - isopropenyl - 8,9 - dimethyl - (1) benzopyrano - (3,4,6) - furo - (2,3,6)(1) - benzopyran 6(6a)H - one; dichlorodiphenyltrichloroethane; 2,2 bis(p - methoxyphenyl) - 1,1,1 - trichloroethane; N [(4 - chlorophenyl)(amino)(carbonyl)] - 2,6 - dif luorobenzamide; dimethyl 2,2 - dichlorovinyl phos phate; 0,0 - dimethyl - 0- (3 - methyl - 4 - nitrophenyl) phosphorothioate; 0,0- dimethyl - 0 - [3- methyl - 4 (methylthio)phenyl] phosphorothioate; 0,0- diethyl - 0 - 0(3,5,6- trichloro - 2 - pyridyl) - phosphorothioate; 0,0 - dimethyl- S - (N - methylcarbomoyl methyl)phosphorothioate; and 0,0 dimethyl phosphorodithioate, S - ester with 4- (mercaptomethyl) - 2 - methoxy - 1,3,4 -thiodiazoline 5-one.

51. Afloating controlled release pesticide dispenseraccording to Claim 50, wherein said porosigen is selected from the group consisting of an oxide and a salt, said oxide and salt having a cation selected from the group consisting of the alkaline metals, the alkaline earth metals, iron, zinc, nickel, silver, and tin, and said salt having an anion selected from the group consisting of a carbonate, bicarbonate, nitrate, nitrite, nitride, peroxide, phosphate, phosphite, phosphide, sulfate, sulfite, and sulfide, which have a solubility of less than 0.1 grams per 100 gramsofwater.

52. A floating controlled release pesticide dispenser according to Claim 51, wherein said polymer is selected from the group consisting of polyethylene including low density polyethylene or high density polyethylene, polypropylene, a copolymer of ethylene-vinyl acetate, polybutene, polystyrene, poly-alpha-methylstyrene, polymethylmethalate, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluorethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon-6, Nylon-6,6, Nylon-6,1 0 polyoxymethylene, polyethyleneterephthalate, cellophane, rayon, a copolymer of ethylene-propylene, and combinations thereof.

53. Afloating controlled release pesticide dispenser according to Claim 52, wherein the amount of said pesticide ranges from 3 to 50 parts, wherein the amount of said organotin compound ranges from 40 to 70 parts, wherein the amount of said porosigen ranges from 15 to 35 parts, and wherein the amount of said porosigenforsaid organotin compound ranges from 25 to 60 parts, and wherein said organotin compound istributyltin oxide ortributyltin fluoride.

54. A floating controlled release pesticide dispenser according to Claim 53, wherein said thermoplastic polymer is selected from the group consisting of polyethylene, a copolymer of ethylenevinylacetate, polypropylene, polystyrene, polyester, and combinations thereof; and wherein said thermoset polymer is selected from the group consisting of epoxy, phonolic, and combinations thereof, and wherein said porosity agent has a porosity of 0.01 grams or less per 100 grams of water.

55. A floating controlled release pesticide dis penser according to Claim 54, wherein said porosity-inducing agent is selected from the group consisting of magnesium carbonate, calcium carbonate, and strontium carbonate.

56. A floating controlled release pesticide dis penser according to Claim 55, wherein said pesticide is selected from the group consisting of tributyltin fluoride, tributyltin oxide, 0,0,0', 0' - tetramethyl - 0,0 -thiodi - p- phenylene phosphorothioate; 0,0 diethyl -0 - (3,5,6 - trichloro - 2 - pyridyl) phosphoro thioate; 0,0 - dimethyl phosphorodithioate ester of diethyl mercaptosuccinate; dimethyl - 1,2 - dibromo - 2,2- dichloroethyl phosphate; 0,0 - dimethyl - 0 (3methyl - 4 - nitrophenyl) phosphorothioate; and combinations thereof.

57. A floating controlled release pesticide dispenser according to Claim 56, wherein said porosigen has a solubility of from 0.1 to 100 grams per 100 grams of water, and wherein the amount of said porosigen ranges from 1 to 60 parts by weight per 100 parts of said polymer.

58. A floating controlled release pesticide dispenser according to Claim 57, wherein said polymer is selected from the group consisting of polyethylene including low density polyethylene or high density polyethylene, a copolymer of ethylenevinylacetate, polypropylene, polybutene, polystyrene, poly- alpha - methylstyrene, polymethylmethalate, polymethylacrylate, polyacry- - late, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluo roethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon-6, Nylon - 6,6, Nylon - 6,10, polyoxymethylene, polyethylene terephthalate, cellophane, rayon, and combinations thereof.

59. Afloating controlled release pesticide dispenser according to Claim 58, wherein the amount of said pesticide ranges from 3 to 50 parts, wherein the amount of said organotin pesticide ranges from 40 to 70 parts, wherein the amount of said porosigen ranges from 2 to 20 parts per 100 parts of polymer, wherein said porosigen is selected from the group consisting of halogenated metals, the halpgenated alkaline earth metals, halogenated nickel, halogenated tin, halogenated silver, ammonium bromide, ammonium carbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, sodium carbonate, and sodium bicarbonate.

60. A floating controlled release pesticide dispenser according to any one of Claims 49,50,52, or 54, wherein said porosigen has a solubility of from 0.1 to 0.0005.

61. A floating controlled release pesticide dispenser according to Claim 39, 41, 42, 44, 47, 49, 50, 52,54,55, 56,57 or 58, wherein said anchor causes said floating dispenserto reside within an aqueous environment.

62. A floating controlled release pesticide dispenser according to Claim 62, wherein said anchor weighs from 2 to 10 times the amount of said floating dispenser.

63. A floating controlled release pesticide dispenser according to Claim 62, wherein said floating dispenser is in the form of strands.

64. Afloating controlled release pesticide dispenser according to Claim 62, wherein said floating dispenser is in the form of a bimodal pellet

65. A floating controlled release pesticide dispenser according to Claim 62, wherein said floating dispenser is in the form of a chip.

66. Afloating controlled release pesticide dispenser according to Claim 47, further comprising a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

67. Afloating controlled release pesticide dispenser according to Claim 47, wherein said porosigen creates a pore structure in said matrix upon exposure to water.

68. A floating controlled release pesticide dispenser according to Claim 47, wherein said matrix further comprises a porosigen modifying agent.

69. A controlled release pesticide dispenser, comprising: a polymer, a pesticide, and a porosigen, said polymer in the form of a matrix and containing said pesticide and said porosigen, the amount of said polymer being 100 parts by weight, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof, said pesticide being a pesticide for destroying animal aquatic pests in an aqueous environment, the amount of said pesticide ranging from 2 parts to 80 parts by weight per 100 parts of said polymer, except when said pesticide is an organotin compound, the amount of said organotin compound ranging from 25 to 75 parts, and said porosigen slowly releasing said pesticide from said polymer, said porosigen having a solubility of 100 grams or less per 100 grams of water.

70. Acontrolled release pesticide dispenser according to Claim 69, wherein said pesticide is selected from the group consisting of tetramethyl - 0,0' - thiodi - p phenylene phosphorothioate; 0,0 - diethyl - 0 - (3,5,6 - trichloro - 2 - pyridyl)phosphorothioate; 0,0dimethyl phosphorodithioate ester of diethyl mercaptosuccinate, a compound having the formula R3SnX where R3 is selected from the group consisting of an alkyl group having from 1 to 8 carbon atoms, an aryl group, and a substituted aryl group wherein said substituted group is an alkyl or an ester containing from 1 to 6 carbon atoms;X is selected from the group consisting of a halogen, an oxide, an alkoxy OR' where R' is an alkyl having from 1 to 12 carbon atoms; 2 - (1 - methylethoxy)phenol methylcarba mate, dimethyl -1,2- dibromo - 2,2- dichloroethyl phosphate; 6,7,8,9,10,10a, - hexachloro - 1,5,5a,6,9,9a- hexahydro -6,9- methano 2,4,3- benzodiox athiepen - 3- oxide; 1 - naphthyl methylcarbamate; gamma -1,2,3,4,5,6 - hexachlorocylohexane; 2 - (1 methylethoxy) phenol methylcarbamate; 1,2,12,12a - tetrahydro - 2- isopropenyl - 8,9 - dimethoxy - (1) benzopyrano - (3,4,6) - furo - (2,3,6)(1 ) - benzopyran 6(6a)H - one; dichlorodiphenyl - trichloroethane; 2,2 - bis(p - methoxyphenyl) - 1,1,1 - trichloroethane; N [(4 - chlorophenyl)(amino)(carbonyl] - 2,6 - difluorobenzamide; dimethyl 2,2 - dichlorovinyl phosphate; 0,0 - dimethyl,0 - (3 - methyl - 4 - nitrophenyl) phosphorothioate; 0,0 - dimethyl - 0 - [3- methyl - 4 methylthio)phenyl]phosphorothioate; 0,0 - diethyl o - (3,5,6 -trichloro -2 - pyridyl)phosphorothioate; 0,0 - dimethyl - S - (N - methylcarbomoyl methyl)phosphorodithioate; and 0,0 - dimethyl phosphorodithioate, S-ester with 4- (mercap tomethyl) - 2 - methoxy - 1,3,4 - thiodiazoline 5-one.

71. A controlled release pesticide dispenser according to Claim 70, wherein said porosigen has a solubility of less than 0.1 grams per 100 grams of water, wherein the amount of said porosigen ranges from 5 to 70 parts except for said organotin com pound in which the amount of porosigen ranges from 15 to 70 parts by weight per 100 parts of polymer.

72. A controlled release pesticide dispenser according to Claim 71, wherein said thermoplastic polymers are selected from the group consisting of polyolefins made from monomers having from 2 to 10 carbon atoms, polystyrene, substituted polys tyrene, the acrylic polymers, the polyvinyl ethers, the polyvinyl acetals, the halogencontaining polymers, the nylons, the polyethers, polyesters, polyurethanes, the cellulose plastics, and combina tions thereof, and wherein said thermoset polymers are selected from the group consisting of phenolics, the epoxides, the amino resins, the unsaturated polyesters, the urethane foams, the silicone polym ers, and combinations thereof.

73. A controlled release pesticide dispenser according to Claim 72, wherein said polymer is selected from the group consisting of polyethylene, low density polyethylene, high density polyethylene, a copolymer of ethylene-vinylacetate, polyp ropylene, polybutene, polystyrene, poly- alpha methylstyrene, polymethylmethalate, polymethylac rylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, polychlorotrif luoroethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon6, Nylon6,6, Nylon-6,10, polyoxymethylene, polyethyleneterephthalate, cellophane, rayon, and combinations thereof.

74. A controlled release pesticide dispenser according to Claim 73, wherein the amount of said pesticide ranges from 3 to 50 parts, wherein the amount of said organotin compound ranges from 40 to 70 parts, wherein the amount of said porosigen ranges from 15 to 35 parts, and wherein the amount of said porosigen for said organotin compound ranges from 25 to 60 parts, and wherein said organo tin compound istributyltin oxide ortributyltin fluoride, and wherein said porosigen has a solubility of less than 0.01 grams per 100 grams of water.

75. A controlled release pesticide dispenser according to Claim 70, wherein said porosigen has a solubility of from 0.1 to 100 grams per 100 grams of water, and wherein the amount of said porosigen ranges from 1 to 60 parts by weight per 100 parts of said polymer.

76. A controlled release pesticide dispenser I according to Claim 75, wherein the amount if said pesticide ranges from 3 to 50 parts, wherein the amount of said organotin pesticide ranges from 40 to 70 parts, wherein the amount of said porosigen ranges from 2 to 20 parts per 100 parts of said polymer, and wherein said polymer is selected from the group consisting of polyethylene including low density polyethylene or high density polyethylene, polypropylene, polybutene, polystyrene, polyalpha-methylstyrene, polymethylmethalate, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, Nylon-6, Nylon-6,6, Nylon-6,1 0, polyoxymethylene, polyethyleneterephthalate, cellophane, rayon, and combinations thereof.

77. A controlled release pesticide dispenser according to Claim 66, wherein said porosigen is selected from the group consisting of halogenated metals, the halogenated alkaline earth metals, halogenated nickel, halogenated tin, halogenated silver, ammonium bromide, ammonium carbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, sodium carbonate, and sodium bicarbonate.

78. A controlled release pesticide dispenser according to Claim 69, further comprising a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

79. Acontrolled release pesticide dispenser according to Claim 69, wherein said porosigen creates a pore structure in said matrix upon exposure to water.

80. A controlled release pesticide dispenser according to Claim 69, wherein said matrix further comprises a porosigen modifying agent

81. A process for the controlled release of a pesticide from a floating dispenser, comprising the steps of: adding and mixing 100 parts by weight of a polymer, from 2 to 80 parts by weight per 100 parts of polymer of a pesticide except when said pesticide is an organotin compound, the amount of said organotin compound ranging from 25 to 75 parts, and a porosigen, said polymer selected from the group consisting of a thermoplastic polymer, a thermoset polymer, and combinations thereof; forming a floating polymer matrix dispenser, said dispenser having a density of lessthan 1.0 grams per cc, attaching said dispenserto an anchor, said anchor having a density of greaterthan 1.0 grams per cc.

82. A process according to Claim 81, wherein said polymer is selected-from the group consisting of polyethylene, a copolymer of ethylenevinylacetate, polypropylene, polystyrene, a polyester and combinations thereof, or in said thennoset polymer which is selected from the group consisting of an epoxy, a phenolic, and combinations thereof, wherein said porosigen is a compound having a solubility of less than 0.01 grams per 100 grams of water, the amount of said porosigen ranging from 5 to 70 parts per 100 parts of polymer, except for said organotin compound in which said porosigen ranges from 15 to 70 parts.

83. A process according to Claim 81, further comprising adding a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

84. A process according to Claim 81, creating a pore structure with said porosigen in said matrix upon exposure to water.

85. A process according to Claim 81, further comprising adding a porosigen modifying agent.

86. A process for slowly releasing a pesticide compound from a dispenser, comprising the steps of: adding and mixing 100 parts by weight of a polymer, a pesticide for use in an aqueous environment for destroying aquatic pests, and a porosigen having a solubility of 100 grams or less per 100 grams of water, the amount of said pesticide ranging from 2 parts to 80 parts by weight per 100 parts of said polymer, except wherein said pesticide is an organotin compound, the amount of said organotin compound ranging from 25 parts to 75 parts by weight per 100 parts of said polymer; and forming a polymer matrix dispenser so that upon contact with an aqueous enviroment, said pesticide is slowly released therefrom.

87. A process according to Claim 86, further comprising adding a second polymer having a melt index, said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units so that a free volume within said dispenser is created.

88. A process according to Claim 86, creating a pore structure with said porosigen in said matrix upon exposure to water.

89. A process according to Claim 86, further comprising adding a porosigen modifying agent.

90. A controlled release herbicide dispenser, comprising: (a) from 10 parts to 160 parts by weight of a herbicide; (b) from 1 partto 80 parts by weight of a porosigen; and (c) 100 parts of a polymer selected from the group consisting of thermoplastic polymers, thermoset polymers, and combinations thereof; said polymer in a matrix containing said herbicide and said porosigen to effect a controlled release of said herbicide, upon contact with water, to retard and eliminate growth of undesired plants.

91. A controlled release herbicide dispenser, according to Claim 90, wherein said polymer has a melt index; wherein said thermoplastic polymers are selected from the group consisting of polyolefins made from monomers having from 2 to 10 carbon atoms, polystyrene, substituted polystyrene, the acrylic polymers, the polyvinyl ethers, the polyvinyl acetals, the halogen-containing polymers, the nylons, the polyethers, polyesters, polyurethanes, the cellulose plastics and combinations thereof, wherein said thermoset polymers are selected from the group consisting of the phenolics, the epoxies, the amino resins, the unsaturated polyesters, the urethane foams, the silicone polymers, and combinations thereof; and wherein said herbicide is selected from the group consisting of 2 - chloro - 2', -6' - diethyl - N - (methoxymethyl)acetanilide; a ,trifluoro - TO - 2,6 - dinitro N,N - dipropyl - p - toluidine; 2 - chloro - N - isopro- pyl acetanilide; 3 - isopropyl - lH - 2,1,3 - benzothiadiazin - (4) 3H - one - 2,2 - dioxide; 4 - amino 6 - (1,1 - dimethylethyl) - 3 - (methylthio) - 1,2,4 - triazin - 5 - (4H) - one; 3,6 - dichloro - 0 - anisic acid; N (phosphonomethyl) glycine isopropylamine salt of Sutan S-ethyl diisobutylthiocarbamate; [4 - (1,1 dimethylethyl) - N - (1 - methylpropyl)] - 2,6 - dinitrobenzenamine; 4 - chloro - 2 - butynyl - m chlorocarbanilate; S - 2,3 - dichloroallyl diisopropylthiocarbamate;S - ethyl dipropylthiocarbamate; 3 (3,4 - dichlorophenyl) - 1 - methoxyl - 1 - methylurea; 1:1 - dimethyl -4,4' - bipyridinium(cation) dichloride; 3 - amino - 2,5 - dichlorobenzoic acid; 1,1 - dimethyl 3- (2,a,a - trifluoro - m - tolyl) urea; 3 - (3,4 - dichlorophenyl) - 1,1 - dimethylurea; ammonium ethyl carbamoylphosphonate; 3,5 - dichloro - N - (1,1 - dimethyl - 2- propyl) - benzamide; 4,amino - 3,5,6- trichloro - picolinic acid;N - (1 - ethylpropyl)3,4 dimethyl - 2,6 - dinitro benzenamine; 3,4 - dichloropropionanalide; 2 - chloro - 4 - ethylamino - 6 - isopropylamino - S - triazine; 2,4 - D acid, 2,4 - dichlorophenoxy acetic acid; 2,3,6 - trichlorophenylacetic acid; 5 - bromo - 3 - sec. - butyl - 6 - methyluracil; 2 chloro - 4,6 - bis(ethylamino) - S - triazine; 6,7 dihydrodipyrido(1 ,2a'2'1' - c)pyrazidiinium dibromide; 2,6 - dichlorobenzonitrile; dimethyl tetrachloroterephthalate; 2 - chloro - 2,6 - diethyl - N - (butoxymethyl)acetanilide; 3,5 - dinitro - N,N - dipropylsulfanilamide; N(cyclopropylmethyl) - a,a,a,trifluoro - 2 - dinitro - N - propyl - p - toluidine; 2,4 - D arnine; dimethylamine salt of 2,4 - dichlorophenoxyacetic acid; 2,4 - D ester; and isooctyl ester of 2,4 - dichlorophenoxy acetic acid.

92. A controlled release herbicide dispenser according to Claim 91, wherein said herbicide has a concentration from 15 parts to 100 parts by weight; wherein said thermoplastic polymer is selected from the group consisting of ethylenepropylene copolymer, polyethylene, including low density polyethylene or high density polyethylene, a copolymer of ethylene-vinyl acetate, polypropylene, polybutene, polystyrene, poly-alpha-methyl styrene, polymethylacrylate, polyacrylate, polymethylmethacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polytetrafluoroethylene, polychloro trifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, NylonS, Nylon-6,6, Nylon-6,1 0, polyoxymethylene, polyethyleneterephthalate, cellophane, rayon and combinations thereof.

93. Acontrolled release herbicide dispenser, according to Claim 92, wherein said herbicide is selected from the group consisting of 2 - chloro - 2', 6' - diethyl - N - (methoxymethyl)acetanilide; a, a, a, trifluoro - 2,6 - dinitro - N,N - dipropyl - p - toluidine; 3,6 - dichloro - 0 - anisic acid; N - (phosphonomethyl)glycine isopropylamine salt of Sutan S - ethyl diisobutylthiocarbamate; 3 - (3,4 - dichlorophenyl) - 1,1 - dimethylurea; 4 - chloro - 2 butynyl - m - chlorocarbanilate; 3,5 - dichloro - N (1,1 - dimethyl - 2 - propyl) - benzamide;N - (1 - ethyl - propyl)3,4 - dimethyl - 2,6 - dinitro benzenamine; 2,4 - dichlorophenoxy acetic acid; 2,3,6 -trich lorophenyl - acetic acid; 5 - bromo - 3 - sec. - butyl - 6 - methyluracil; 2 - chloro - 4 - ethylamino - 6 - isop ropylam ino - S -triazine; 2 - chloro -4,6- bis(ethylamino) - S - triazine; 6,7- dihydrodipyrid ozl,2a'2'1' - c)pyrazidiinium dibromide; 2,6 - dich lorobenzonitrile; dimethylamine salt of 2,4 - dich lorophenoxyacetic acid; isooctyl ester of 2,4 - dich lorophenoxy acetic acid and the butoxyethanol ester thereof; and wherein said herbicide is in a concentration from 20 parts to 50 parts by weight

94.A controlled release herebicide dispenser according to Claim 93, wherein said herbicide is selected from the group consisting of a,or,a, trifluoro - 2,6 - dinitro - N,N - dipropyl - p - toluidine; N (phosphonomethyl)glycine isopropylamine salt of Sutan S - ethyl diisobutylthiocarbamate; 3 (3,4 - dichlorophenyl) -1,1 - dimethylurea; 3,5 - dichloro N - (1,1 - dimethyl - 2 - propyl) - benzamide; 2,3,6 trichlorophenylacetic acid; 5 - bromo - 3 - sec. - butyl - 6 - methyluracil; 6,7 - dihydrodipyrido(1,2a'2'1' c)pyrazidiinium dibromide; 2 chloro - 2', - 6' diethyl - N - (methoxymethyl) acetanilide; 2,6- dichlorobenzonitrile; dimethylamine salt of 2,4 - dichlorophenoxyacetic acid; and isooctyl ester of 2,4 dichlorophenoxy acetic acid; wherein said thermoplastic polymer is selected from the group consisting of ethylenepropylene copolymer, polyethylene including high density or low density polyethylene, a copolymer of ethylenevinyl acetate, polystyrene, polypropylene, polyester, and combinations thereof; and wherein said thermoset polymer is selected from the group consisting of a phenolic, an epoxy, and combinations thereof.

95. Acontrolled release herbicidedispenser, according to Claim 91, wherein said porosigen has a solubility of from 0.1 to 100 grams per 100 grams of water.

96. A controlled release herbicide dispenser, according to Claim 95, wherein said porosigen has a concentration of from 1 part to 40 parts by weight; and wherein said porosigen is selected from the group consisting of the salts, hydrates, and oxides of alkaline metals, alkaline earth metals,nickel, tin, and silver; and ammonium bromide, ammonium carbonate, ammonium bicarbonate, ammonium chlorate, ammonium chloride, ammonium fluoride, ammonium sulfate, sodium carbonate, and sodium bicarbonate.

97. A controlled release herbicide dispenser according to Claim 96, wherein said porosigen has a concentration from 1 part to 30 parts by weight and; wherein said porosigen is selected from the group consisting of ammonium sulfate, ammonium bicar bonate, sodium bicarbonate, sodium carbonate, ammonium chloride, and ammonium chlorate.

98. A controlled release herbicide dispenser according to Claim 97, wherein said porosigen has a concentration from 12 parts to 25 parts by weight; and wherein said porosigen is selected from the group consisting of sodium bicarbonate, sodium carbo nate, and ammonium sulfate.

99. A controlled release herbicide dispenser, according to Claim 91, wherein said porosigen has a solubility of less than 0.1 grams per 100 grams of water; and wherein the amount of said porosigen ranges from 5 parts to 70 parts by weight

100. A controlled release herbicide dispenser, according to Claim 99, wherein said porosigen is selected from the group consisting of an oxide and a salt, said oxide and salt having a cation selected from the group consisting of the alkaline metals, the alkaline earth metals, iron, zinc, nickel, silver and tin, and said salt having an anion selected from the group consisting of a carbonate, bicarbonate, nitrate, nitrite, nitride, peroxide, phosphate, phosphite, phosphide, sulfate, sulfite, sulfide, and said porosigen having a solubility of at less than 0.01 grams per 100 grams of water.

101. Acontrolled release herbicide dispenser, according to Claim 100, wherein said porosigen has a solubility of from 0.0005 to 0.01 grams per 100 grams of water.

102. A controlled release herbicide dispenser, according to Claim 101, wherein said porosigen is selected from the group consisting of carbonates of magnesium, calcium, and strontium cations, and combinations thereof.

103. Acontrolled release herbicide dispenser, according to either of Claims 95 or 99, wherein the soil moisture removes said porosigen and creates a pore structure in the dispenser.

104. Acontrolled release herbicide dispenser, according to any one of Claims 91,95, or 99, further comprising from 1 part to 25 parts by weight of a hygroscopic compound.

105. Acontrolled release herbicide dispenser according to Claim 104, wherein said hygroscopic compound is selected from the group consisting of Cadiz P2Os, Mg(ClO4)2, KOH, ACO, Ba(C104), and combinations thereof.

106. A controlled release herbicide dispenser, according to any of Claims 91,95 or 99, further comprising from 2 parts to 6 parts by weight of a glycol, silicon dioxide, soy oil, and combinations thereof; said glycol selected from the group consisting of a lower aliphatic glycol, a glycerol glycol, and combinations thereof.

107. Acontrolled release herbicide dispenser, according to any one of Claims 91,95 or 99, further comprising from 2 parts to 25 parts of soy oil, silicon dioxide, and combinations thereof.

108. Acontrolled release herbicide dispenser, according to any one of Claims 91,95 or 99, further comprising a second polymer having a melt index; said second polymer index having a disparity from said first polymer melt index of from 5 to 25 melt index units, whereby a free volume within the dis penser is created.

109. A controlled release herbicide dispenser, according to any one of Claims 91 to 108, wherein the dispenser has a density of less than 1.0 grams per cubic centimeter of water; and the dispenser further comprising an anchor, said anchor having a density of greater than 1.0 grams per cubic centimeter and connected to the dispenser, whereby the dispenser is buoyed to said anchor in aquatic environments.

110. Acontrolled release herbicide dispenser, according to Claim 109 wherein said anchor weighs from 2 to 10 times the weight of the dispenser.

111. A controlled release herbicide dispenser, according to Claim 109, wherein the dispenser is in the form of a plutality of strands.

112. A controlled release herbicide dispenser, according to Claim 109, wherein the dispenser is in the form of a multi-modal pellet.

113. A controlled release herbicide dispenser, according to Claim 109, wherein the dispenser is in the form of a chip.

114. A process for the controlled release of a herbicide from a dispenser, comprising: (a) adding and mixing 100 parts by weight of a polymer, from 10 parts to 160 parts by weight of a herbicide, and from 1 part to 80 parts by weight of a porosigen; (b) forming a matrix from said polymer within which said porosigen and said herbicide are dispersed; and (c) applying and contacting said matrix with the environment so that, upon contact with water, said herbicide will be released to retard and eliminate undesired plant growth.

115. A process for the controlled release of a herbicide from a dispenser, according to Claim 114, wherein said adding and mixing further comprises adding and mixing from 1 partto 25 parts of a hygroscopic compound.

116. A process for the controlled release of a herbicide from a dispenser, according to Claim 114, wherein said contacting comprises buoying the matrix in an aquatic environment.

117. A method for the controlled release of herbicides into an environment, comprising: (a) dispersing a matrix into the environment, said matrix comprising a polymer, a herbicide, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said herbicide through said pore structure from said matrix upon contact with water, said herbicide to retard and eliminate growth in undesired plants; and said porosigen having a water solubility less than 100 grams per 100 grams of water and said polymer being water insoluble and non-porous.

118. A method for the controlled release of herbicides into an environment, according to Claim 117, wherein said matrix further comprises a hygroscopic compound.

119. A method for the controlled release of herbicides into an environment, according to Claim 117, wherein said dispersing comprises contacting said matrix with the terrestial environment.

120. A method for the controlled release of herbicides into an environment, according to Claim 117, wherein said dispersing comprises buoying said matrix in an aquatic environment.

121. A composition for destroying pestiferous plants, comprising: a mixture of a herbicidally effective active ingredient which is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams of water at 25 degrees C; said mixture being dispersed within a water insoluble, non-porous polymeric matrix; the proportion of particulate material being suffi cientto induce liquid porosity in said matrix upon exposure to water

122.A method for the controlled release of a plant nutrient into an environment, comprising: (a) dispersing a matrix into the environment, said matrix comprising a polymer, a plant nutrient, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said plant nutrient through said pore structure from said matrix upon contact with water, said plant nutrient stimulating plant growth; and said porosigen having a water solubility less than 100 grams per 100 grams of water and said polymer being water insoluble and non-porous.

123. A method for the controlled released of plant nutrients into an environment, according to Claim 122, wherein said matrix further comprises a porosigen modifying agent.

124. A method for the controlled release of plant nutrients into an environment, according to Claim 122, wherein said dispersing comprises contacting said matrix with the terrestial environment.

125. A composition for stimulating plant growth comprising: a mixture of a plant nutriently effective active ingredient which is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams of water at 25 degrees C; said mixture being dispersed within a water insoluble, non-porous polymeric matrix; the proportion of particulate material being sufficient to induce the liquid porosity in said matrix upon exposureto water.

126. A method for the controlled release of plant regulants into an environment, comprising: (a) dispersing a matrix into the environment, said matrix comprising a polymer, a plant regulant, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said plant regulantthrough said pore structure from said matrix upon contact with water, said plant regulant regulating growth of plants; and said porosigen having a water solubility less than 100 grams per 100 grams of water and said polymer being water insoluble and none-porous.

127. A method for the controlled release of plant regulant into an environment, according to Claim 126, wherein said matrix further comprises a porosigen modifying agent.

128. A method for the controlled release of plant regulant into an environment, according to Claim 126, wherein said dispersing comprises contacting said matrix with the terrestrial environment

129. A composition for regulating plant growth comprising; a mixture of a plant regulantly effective active ingredientwhich is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams of water at 25 degrees C; said mixture being dispersed within a water insoluble, non-porous polymeric matrix; the proportion of particulate material being sufficient to induce liquid porosity in said matrix upon exposure to water.

130. A method for the controlled release of soil compound into an environment, comprising: (a) dispensing a matrix into the environment, said matrix comprising a polymer, a soil compound selected from the group consisting of a nematicide, a soil insecticide, and combinations thereof, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said soil compound through said pore structure from said matrix upon contact with water, said soil compound to retard or destroy soil pest; and said porosigen having a water solubility less than 100 grams per 100 grams of water and said polymer being water insoluble and non-porous.

131. Amethodforthecontrolled release of soil compound into an environment, according to Claim 130, wherein said matrix further comprises a porosigen modifying agent.

132. A method for the controlled release of soil compound into an environment, according to Claim 130, wherein said dispersing comprises contacting said matrix with the terrestial environment

133. A composition for destroying soil pests, comprising: a mixture of a soil pesticidally effective active ingredient which is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams of water at 25"C; said mixture being dispersed within a water insoluble, non-porous polymeric matrix; the proportion of particulate material being suffi cientto induce liquid porosity in said matrix upon exposure to water.

134. A method for the controlled release of pesticides from a floating dispenser into an aquatic environment, comprising: (a) dispersing a floating matrix into the environment, said matrix comprising a polymer, a pesticide for destroying aquatic pests, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said pesticide through said pore structure from said matrix upon contact with water, said pesticide to retard or destroy undesired pests; said porosigen having a water solubility lessthan 100 grams per 100 grams of water and said polymer being water insoluble and non-porous; said dispenser having a density of less than 1.0 grams per cc; and an anchor, said anchor having a density of greater than 1.0 grams per cc and connected to said dis pensen

135. A method forthe controlled release of pesticides into an environment, according to Claim 134, wherein said matrix further comprises a porosigen modifying compound.

136. A method for the controlled release of pesticides into an environment, according to Claim 134, wherein said dispersing comprises contacting said matrix with the aquatic environment.

137. A composition for destroying aquatic pests, comprising: a mixture of an aquatic pesticidally effective active ingredient which is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams of water at 25"C; said mixture being dispersed within a water insoluble, non-porous polymer matrix, and being floatable; the proportion of particulate material being sufficientto induce liquid porosity in said matrix upon exposure to water; and an anchor, said anchor connected to said floatable mixture.

138. A method for the controlled release of pesticides in an environment, comprising: (a) dispersing a matrix into the environment, said matrix comprising a polymer, a pesticide for destroying pests, and a porosigen; (b) dissolving said porosigen from said matrix at a controlled rate upon contact with water, to create a pore structure in said matrix; (c) dislodging said pesticide through said pore structure from said matrix upon contact with water, said pesticide to retard or destroy undesired pests; and said porosigen having a water solubility less than 100 grams per 100 grams of water and said polymer being water insoluble and non-porous.

139. A method for the controlled release of pesticides into an environment, according to Claim 138, wherein said matrix further comprises a porosigen modifying compound.

140. A method for the controlled release of pesticides into an environment, according to Claim 138, wherein said dispersing comprises contacting said matrix with the environment.

141. Acomposition for destroying aquatic pests, comprising: a mixture of a pesticidally effective active ingredientwhich is water dispersible and an inert particulate material having a water solubility from less than 100 grams per 100 grams ofwaterat250C; said mixture being dispersed within a water insoluble, non-porous polymer matrix; the proportion of particulate material being suffi cientto induce liquid porosity in said matrix upon exposure to water.

142. A controlled release of compounds utilizing a plastic dispenser with a porosigen contained therein substantially as herein before described with reference to the accompanying drawings.